Message from Division Chair
The field of condensed matter physics, which overlaps with chemistry, materials science, and engineering, attempts to understand the physical properties of materials. This includes a broad range of topics including but not limited to:
- Structural, Electronic, Dielectric, Electrical, Magnetic, and Optical Properties of Materials;
- Novel Quantum Materials – superconductors, topological insulators, Weyl semimetal,s and quantum spin liquids;
- Magnetoelectric and multiferroic materials;
- 2D and 3D Magnetic Systems;
- Quantum Hall Effect;
- Energetic Materials
- Semiconductors, Photovoltaics, Optoelectronics and Photonics;
- Magneto-Transports, Magnetic Interfaces and Spintronics;
- Complex Oxides and Emergent Phenomena.
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Invited Speaker
Probing the connection between magnetism and itinerant electrons in the layered Dirac semimetal EuAuSb
The interaction between itinerant electrons and magnetism is of particular interest in compounds within which the ordered moments are compensated. We have studied EuAuSb, in which triangular Eu layers are separated by hexagonally ordered layers of Au and Sb. Our neutron diffraction study [1] has demonstrated that the individual Eu layers order ferromagnetically, while the spin directions of neighboring layers rotate in a helical fashion with a unit cell of approximately 3 Eu layers. This order is consistent with competing RKKY interlayer exchange couplings. It also produces a Zeeman field that leads to spin-splitting of Fermi pockets. These results and more will be discussed.
1. J. Sears, J. Yao, Z. Hu, W. Tian, N. Aryal, W. Yin, A.M. Tsvelik, I.A. Zaliznyak, Q. Li, and J.M. Tranquada, “EuAuSb: An incommensurate helical variation on an altermagnet” (to be submitted).
Division Schedule
Please look below for detailed schedule.
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Abstract Number: ANPA2025-N00045 Presenting Author: Ashwin Thapa Magar Co-Authors: Tu Anh Ngo, Yiping Zhao, Tho Duc Nguyen Presenter's Affiliation: University of Georgia, Athens, GA, USA Title: Hysteresis-free Near-Infrared Optical Hydrogen Sensor Based on Ti/Pd/Teflon AF Thin Film Location: Virtual Presentation Show/Hide Abstract Palladium (Pd) and titanium (Ti) exhibit opposite changes in their dielectric properties during hydrogenation with the most pronounced effects occurring at longer wavelengths. This contrasting behavior motivates the exploration of their combined optical properties in Ti/Pd bilayer films with varying Pd and Ti thickness across the visible to near-infrared spectrum (400–1600 nm). Here, we investigate the optical properties of Teflon AF (TAF)-coated titanium-palladium (Ti/Pd) bilayer thin films fabricated via sequential electron-beam evaporation and tested using optical transmission measurements under repeated hydrogenation cycles. The Ti/Pd/TAF architecture significantly enhances hydrogen-induced NIR optical contrast—demonstrating a 2.7× improvement over a Pd/TAF reference film at 1600 nm—through hydrogen ion transfer from Pd to Ti. Based on this design, we demonstrate a hysteresis-free optical hydrogen sensor operating in the NIR, capable of detecting hydrogen concentrations below 10 ppm. The optimized structure (5 nm Ti / 1.9 nm Pd / 30 nm TAF) exhibits a sub-second response time (t90 < 0.4 s) at 4% H2, high selectivity with negligible interference from CO2, CH4, and CO, and stable performance with less than 6% signal degradation over 135 hydrogenation cycles. These results establish a simple, scalable platform for high-performance, room-temperature hydrogen sensing with strong potential for energy and safety monitoring applications.
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Abstract Number: ANPA2025-N00049 Presenting Author: Ashna Upreti Co-Authors: Chandra M. Adhikari Presenter's Affiliation: Jack Britt High School, Fayetteville, NC 28306, USA Title: Structural stability and electronic structure of (Ti,Ta)4C3 MXenes Location: Virtual Presentation Show/Hide Abstract Using Vienna Ab initio Simulation Package called VASP, the first-principles calculations are performed to study the structural relationship of TixTa4-xC3 (with x = 0, 4) MXenes to their electronic and optical properties in the framework of Density Functional Theory (DFT). Electron–ion interactions are taken care of employing the projector augmented wave (PAW) pseudopotentials, and the generalized gradient approximation, parametrized by Perdew, Burke, and Ernzerhof (GGA-PBE) functional is used for the exchange–correlation in the system. All TixTa4-xC3 Mxenes are found metallic. In single transition metal M4C3 Mxenes where M= Ti or Ta, the density of states are dominated by the outermost d-states of respective M metal and 2p states of C. The domination of M-nd (n= 3 or Ti and 5 for Ta) over C-2p states is larger at the Fermi level and conduction band. Strong Ti-3d to Ta-5d hybridization exists in double transition metal TixTa4-xC3 MXenes, where x = 1 to 3. Ordered double transition metal MXene Ti2Ta2C3 is one of the desired MXenes for electrochemical applications. Lithium discharge process is comparatively more favorable in Ti2Ta2C3 than other double and single transition metal TixTa4-xC3 MXenes.
This work is supported by the Department of Energy BES-RENEW award number DE-SC0024611.
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Abstract Number: ANPA2025-N00051 Presenting Author: Anup Pradhan Sakhya Co-Authors: Brenden R. Ortiz; Barun Ghosh; Milo Sprague; Mazharul Islam Mondal; Matthew Matzelle; Nabil Atlam; Iftakhar Bin Elius; Nathan Valadez; Arun K Kumay; David G. Mandrus; Jonathan D. Denlinger; Arun Bansil; Madhab Neupane Presenter's Affiliation: University of Central Florida Title: Diverse electronic topography in a distorted kagome metal LaTi3Bi4 Location: Virtual Presentation Show/Hide Abstract Recent reports on a family of kagome metals of the form LnTi3Bi4 (Ln = Lanthanide) has stoked interest due to the combination of highly anisotropic magnetism and a rich electronic structure. The electronic structure near the Fermi level is proposed to exhibit Dirac points and van Hove singularities. In this manuscript, we use angle-resolved photoemission spectroscopy measurements in combination with density functional theory calculations to investigate the electronic structure of a newly discovered kagome metal LaTi3Bi4. Our results reveal multiple van Hove singularities (VHSs) with one VHS located in the vicinity of the Fermi level. We clearly observe two flat bands, which originate from the destructive interference of wave functions within the Ti kagome motif. These flat bands and VHSs originate from Ti d-orbitals and are very responsive to the polarization of the incident beam. We notice a significant anisotropy in the electronic structure, resulting from the breaking of six-fold rotational symmetry in this material. Our findings demonstrate this new family of Ti based kagome material as a promising platform to explore novel emerging phenomena in the wider LnTi3Bi4 (Ln= lanthanide) family of materials.
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Abstract Number: ANPA2025-N00053 Presenting Author: Nathan Valadez Co-Authors: Nathan Valadez; Milo Sprague; Iftakhar Bin Elius; Anup Pradhan Sakhya; Dante James; Peter Radanovich; Tetiana Romanova; Sami Elgalal; Grzegorz Chajewski; Andrzej Ptok; Dariusz Kaczorowski; Madhab Neupane Presenter's Affiliation: University of Central Florida Title: Electronic structure of rare earth based ternary nodal line semimetal Location: Virtual Presentation Show/Hide Abstract Lanthanide-based LnSbTe materials offer an opportunity to explore the interplay of magnetism and topological properties, driven by nonsymmorphic crystalline symmetry, interactions with rare-earth 4f orbitals, and strong spin-orbit coupling (SOC). In this study, we investigate the electronic structure of a member of the LnSbTe family that crystallizes in the ZrSiS-type nonsymmorphic tetragonal structure. Through comprehensive low-temperature bulk measurements, we identify antiferromagnetic ordering below 7.45 K, with an additional phase transition at 7.15 K. Through the usage of angle-resolved photoemission spectroscopy measurements, we reveal a roughly diamond-shaped Fermi pocket within the kz=0 plane, however with a reduced spectral intensity along the Γ-M direction resulting from strong spin orbit interactions. These findings, supported by density-functional theory calculations, emphasizes its potential as a platform for investigating the intricate interplay between topology, magnetism, and SOC in quantum materials.
*M.N. acknowledges support from the National Science Foundation under CAREER award DMR-1847962, the NSF Partnerships for Research and Education in Materials (PREM) Grant DMR-2121953, and the Air Force Office of Scientific Research MURI Grant No. FA9550-20-1-0322.
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Abstract Number: ANPA2025-N00054 Presenting Author: Himanshu Sheokand Co-Authors: Anup Pradhan Sakhya; Richa Pokharel Madhogaria; Barun Ghosh; Nabil Atlam; Milo Sprague; Mazharul Islam Mondal; Arun K. Kumay; Shirin Mozaffari; Rui Xue; Yong P. Chen; David G. Mandrus; Arun Bansil; Madhab Neupane Presenter's Affiliation: PhD Student at University of Central Florida Title: Observation of Dirac cone and flat band in an in-plane ferromagnetic Kagome Metal Location: Virtual Presentation Show/Hide Abstract The intricate interplay between flat bands, Dirac cones, and magnetism in Kagome materials has recently drawn significant attention from materials scientists, particularly in compounds belonging to the RMn6Sn6 (R = Sc, Y, Rare-earths) family due to inherent magnetic frustration. Here, we present a comprehensive analysis encompassing angle-resolved photoemission spectroscopy (ARPES), magneto-transport measurements, and density functional theory (DFT) calculations of the ferromagnetic (FM) kagome magnet ScMn6(Sn0.78Ga0.22)6. Our findings reveal a paramagnetic to FM transition at 375 K, with the easy axis of magnetization aligned along the in-plane axis. Notably, we observe a significant anomalous Hall effect, attributed to the presence of a Dirac cone near the Fermi energy, as indicated by ARPES measurements. Overall, our study provides valuable insights into the electronic structure of magnetic kagome materials and lays the groundwork for discovering novel topological phases within this class of materials.
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Abstract Number: ANPA2025-N00055 Presenting Author: Arun Kumar Kumay Co-Authors: Milo sprague; Anup Pradhan Sakhya; Barun Ghosh, Mazharul Islam Mondal; Iftakhar Bin Elius; Nathan Valadez; Tetiana Romanova; Dariusz Kaczorowski; Arun Bansil; Madhab Neupane Presenter's Affiliation: University of central Florida Title: Observation of Electronic Structure Reconfiguration across the N´eel Transition in EuZn2As2 Location: Virtual Presentation Show/Hide Abstract Magnetoresistive materials have been tremendously important for the development of magnetic memory storage and spintronic devices. Recently, the antiferromagnetic EuX2Pn2 compounds, with X being a transition metal and Pn being a pnictogen, have seen intensive research interest due to their unusual anomalous Hall effect behavior and pronounced resistive anomaly near the N´eel transition. These magnetotransport phenomena have been interpreted in the context of short-ranged ferromagnetic fluctuations, magnetic polaron formation, canted spin configurations, and temperature-dependent metal-insulator transitions in the electronic structure. Here, we report
the observation of such a pronounced resistivity anomaly in EuZn2As2 near TN = 19 K. We
demonstrate the suppression of this anomaly using applied magnetic fields, both in-plane and out-of-plane. To further interpret the origin of the observed transport behavior, we performed a study of the temperature-dependent electronic structure using combined angle-resolved photoemission spectroscopy (ARPES) and first-principles density functional theory (DFT) calculations, which produce limited modifications to the bands across the N´eel transition away from the Fermi energy. This lack of involvement of the electronic structure indicates a spin-scattering origin of the aforementioned transport properties, rather than a reconstruction of the Fermi surface.
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Abstract Number: ANPA2025-N00040 Presenting Author: John Tranquada (Invited) Co-Authors: nan Presenter's Affiliation: Brookhaven National Laboratory, New York USA Title: Probing the connection between magnetism and itinerant electrons in the layered Dirac semimetal EuAuSb Location: Virtual Presentation Show/Hide Abstract The interaction between itinerant electrons and magnetism is of particular interest in compounds within which the ordered moments are compensated. We have studied EuAuSb, in which triangular Eu layers are separated by hexagonally ordered layers of Au and Sb. Our neutron diffraction study [1] has demonstrated that the individual Eu layers order ferromagnetically, while the spin directions of neighboring layers rotate in a helical fashion with a unit cell of approximately 3 Eu layers. This order is consistent with competing RKKY interlayer exchange couplings. It also produces a Zeeman field that leads to spin-splitting of Fermi pockets. These results and more will be discussed.
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Abstract Number: ANPA2025-N00056 Presenting Author: Mazharul Islam Mondal Co-Authors: Anup Pradhan Sakhya ; Milo Sprague; Brenden R. Ortiz; Matthew Matzelle; Arun K. Kumay; Himanshu sheukand; Barun Ghosh; Arun Bansil; and Madhab Neupane Presenter's Affiliation: University of Central Florida Title: Studying the electronic band structure of a Ferromagnetic distorted Kagome metal NdTi3Bi4 Location: Virtual Presentation Show/Hide Abstract Kagome materials have garnered significant attention in recent years due to their rich topological phases and the prominent role of electronic correlations. In this study, we explore the electronic structure of NdTi₃Bi₄, a distorted ferromagnetic Kagome metal with a transition temperature of 9 K. Our analysis combines angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT) calculations. We identify two flat bands that arise from the Kagome lattice formed by Ti atoms, primarily contributed by the Ti dxy and Ti dx2- y2 orbitals. Additionally, multiple van Hove singularities (VHSs) are observed, with one located near the Fermi level. ARPES measurements reveal a Dirac cone at the K point, a feature that is further supported by our DFT results. Together, these findings provide a comprehensive understanding of the electronic properties of NdTi₃Bi₄, highlighting its potential as a platform for studying correlation-driven phenomena in ferromagnetic Kagome systems.
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Abstract Number: ANPA2025-N00057 Presenting Author: Peter Radanovich Co-Authors: Peter Radanovich (UCF); Milo Sprague (UCF); Nathan Valadez (UCF); Iftakhar Bin Elius (UCF) Dante James (UCF); Sabin Regmi (Idaho National Laboratory); Volodymyr Buturlim (INL); Anup Pradhan Sakhya (UCF); Mazharul Islam Mondal (UCF); Raman Shankar (Academia Sinica); Krzystoff Gofryk (INL); Madhab Neupane (UCF) Presenter's Affiliation: University of Central Florida Title: Influence of Magnetic Ordering and Monoclinic Distortion on the Electronic Structure in a Rare Earth-based Nodal Semimetal Location: Virtual Presentation Show/Hide Abstract Magnetic topological semimetals have been the subject of intense research interest, due to the interdependence of topological electronic states with the magnetic structure. The LnSbTe family of compounds, Ln being a lanthanide element, is a well-established group of magnetic topological nodal line semimetals that crystallize in the tetragonal ZrSiS-type structure. In this work, we investigate a new compound related to the LnSbTe family, exhibiting a subtle monoclinic distortion and an elevated antiferromagnetic transition temperature. An investigation into the electronic structure modifications due to crystallographic distortion and the onset of magnetic ordering is warranted. Here, we present the results of a high-resolution angle-resolved photoemission spectroscopy and density functional theory study, where we compare and contrast the observed Fermi surface, constant energy contours, and electronic band dispersions with the LnSbTe compounds. This work highlights the matieral’s potential as a versatile platform for exploring the interplay of the complex interactions between topology and magnetism in quantum materials.
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Abstract Number: ANPA2025-N00058 Presenting Author: Raj Kumar Paudel Co-Authors: nan Presenter's Affiliation: Research Center for Applied Science, Academia Sinica, Taiwan Title: Electric-Field-Enhanced Interlayer Exciton Brightening in Bilayer WSeâ‚‚ Location: Virtual Presentation Show/Hide Abstract We present the first theoretical framework explaining the experimentally observed brightening of interlayer excitons (A_1s^12, B_1s^12 and 2s state A_2s^12 ) in dual-gated bilayer WSeâ‚‚ under vertical electric fields. While a phenomenological two-level coupling model can fit the observed linear Stark shift and oscillator strength enhancement, it overestimates interlayer coupling strengths and lacks physical insight. Our microscopic hole-tunneling model demonstrates that electric fields redistribute hole wavefunctions across layers, enabling symmetry-allowed interlayer tunneling and exciton hybridization. This mechanism naturally explains both the 1s and 2s Rydberg states while predicting accurate coupling strengths. The model reveals that hole tunneling - rather than dipole coupling - dominates the brightening process at moderate fields, providing a fundamental understanding of the wavefunction evolution governing oscillator strength enhancement. These findings establish bilayer WSeâ‚‚ as an ideal platform for electrically tunable excitonic effects while offering a general theoretical approach for designing optoelectronic devices based on interlayer excitons in van der Waals heterostructures.
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Abstract Number: ANPA2025-N00063 Presenting Author: Pratiksha Khanal Co-Authors: nan Presenter's Affiliation: Central Department of Physics Title: ELECTRONIC AND MAGNETIC PROPERTIES OF NiGa2S4 and Ni{1-x}CoxGa2S4 Location: Virtual Presentation Show/Hide Abstract Layered materials, with their anisotropic properties, are promising for spintronic applications, including spin-based devices and quantum technologies. The electronic and magnetic properties of layered materials NiGa2S4 and Ni{1-x}CoxGa2S4 were explored through density functional theory. The Virtual Crystal Approximation (VCA) approach, implemented within the FPLO code, was used to simulate Co doped at the Ni site ( Ni{1-x}CoxGa2S4 , x = 0.05, 0.1, 0.15, 0.2, 0.25 ), using both GGA and GGA+U functionals using the full-potential local orbital (FPLO) code. This study shows NiGa2S4 an antiferromagnetic ground state with indirect band gap semiconductor, with band gap value 0.178 eV in GGA and 1.096 eV in GGA+U calculation, when U = 4 eV. While the monolayer structure exhibits an ferromagnetic ground state with a semiconducting nature. The density of state analysis reveals that S-3p orbital hybridized with Ni- 3d orbital in valance band, while the conduction band comes from Ni -3d orbital. Co doping at the Ni site increase atomic size, enhances orbital overlap, and strengthens bonding, which increases the band gap as the concentration increases from 5% to 25%, which shift the conduction and valence bands closer together. This study demonstrate the significant impact of transitioning from 3D to 2D on the electronic structure and highlighting the potential of Co doping in tailoring its properties for future technological applications.
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Abstract Number: ANPA2025-N00064 Presenting Author: Mackenzie Songsart-Power Co-Authors: Brady Wilson; Joseph W. Phalen; Chetan Dhital; Tej B. Limbu Presenter's Affiliation: Department of Physical and Applied Sciences, University of Houston-clear Lake Title: Is 2D Nb2CTX MXene Suitable for Surface-Enhanced Raman Scattering Applications? Location: Virtual Presentation Show/Hide Abstract MXenes have attracted considerable attention for surface-enhanced Raman scattering (SERS) applications owing to their outstanding electronic properties and excellent hydrophilicity. Despite this, niobium carbide (Nbâ‚‚CTâ‚“), a prominent member of the MXene family, remains relatively underexplored in the context of SERS. In this study, we present a comprehensive evaluation of the SERS activity of Nbâ‚‚CTâ‚“ nanosheets using methylene blue (MB) and crystal violet (CV) as probe molecules under 532 nm and 488 nm laser excitations. The Raman enhancement factors (EFs) for MB and CV with 532 nm excitation were found to be 2.12 × 10ⶠand 2.65 × 10â´, respectively. The significantly higher enhancement observed for MB, two orders of magnitude greater than that for CV, is attributed to a light-induced resonance charge transfer process between MB and Nbâ‚‚CTâ‚“. Our findings suggest that the Raman enhancement of the probe molecules is determined by the interplay between the excitation energy and the electronic properties of both the SERS substrate and the probe molecules. SERS measurements performed under 488 nm excitation further support the proposed charge transfer mechanism. Additionally, the SERS performance of Nbâ‚‚CTâ‚“ was benchmarked against other MXenes and conventional SERS substrates. While Nbâ‚‚CTâ‚“ may not achieve single-molecule detection sensitivity, it demonstrates sufficient enhancement to detect various chemical and environmental analytes with practical sensitivity. These results offer valuable insights into the charge transfer-based SERS mechanism and highlight the potential of Nbâ‚‚CTâ‚“ as a cost-effective, 2D MXene-based substrate for molecular sensing applications.
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Abstract Number: ANPA2025-N00065 Presenting Author: Francisco Seva Sotomayor Co-Authors: Svetlana Kilina; Dinesh Thapa Presenter's Affiliation: Department of Mathematics and Physics, Thomas More University Title: Opto-electronic tuning in Stone-Wales defect (11,0) single walled carbon nanotube Location: Virtual Presentation Show/Hide Abstract Stone-Wales (SW) defects, which are found in stable form in carbon nanostructures, have
significant influence on the electronic, optical, and mechanical properties. These defects can be created by local rotating of a C–C bond by 90° resulting in two pentagons connected by a pair of heptagons which exist in two different topological orientations, axial and circumferential. In this work, we have investigated the structural, electronic, and optical properties of the (11,0) semiconducting zigzag single walled carbon nanotube (CNT) using density functional theory (DFT) based on periodic plane wave basis sets. Our calculated results reveal the fact that the axial SW defects are generally more stable than circumferential ones. Zigzag single walled CNT consists of a donor-π-acceptor framework, in which the Stone-Wales defect ring serves as an electron donor while the zigzag nanotube works as an electron acceptor. It has been observed that the two different orientations of SW defects, i.e. longitudinal and circumferential SW defects, on carbon nanotubes (CNTs) result in two different electronic structures with a reduced electronic band gap corresponding to near infra-red wavelength associated with optically active lowest lying transition compared to dark transition in pristine. Further, the circumferential SW defect is optically active compared to the axial one, whose strength increases with the increasing defect-defect interaction.
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Abstract Number: ANPA2025-N00066 Presenting Author: Rajendra Prasad Gautam Co-Authors: Tochukwu P. Okonkwo2; Jacob Limburg2; Bowen Houser3; William G. Pitt3; Roger G. Harrison2; Karine Chesnel1 Presenter's Affiliation: Brigham Young University Title: Effects of nano-sizing on the Verwey transition in Fe3O4 NPs Location: Virtual Presentation Show/Hide Abstract This study examines the Verwey transition in magnetite (Fe₃O₄) nanoparticles synthesized through an organic solution-based approach, elucidating the relationship between nanoscale structural and magnetic properties. Comprehensive characterization via scanning electron microscopy (SEM) revealed monodisperse nanoparticles with controlled size distributions ranging from 27 to 125 nm. X-ray diffraction (XRD) analysis confirmed phase-pure, crystalline nanoparticles adopting the cubic inverse spinel structure of magnetite. Vibrating sample magnetometry (VSM) demonstrated distinct magnetic behavior, including saturation magnetization, coercivity, and temperature-dependent hysteresis, with the Verwey transition temperature (T_V) observed at values significantly lower than the bulk counterpart (125 K). This suppression of T_V is ascribed to nanoscale effects such as finite-size confinement, surface spin disorder, anisotropic morphology, and crystallographic imperfections. The results underscore the critical role of particle dimensions, geometric anisotropy, and interfacial dynamics in modulating the Verwey transition, providing a framework for engineering magnetic nanoparticles with tailored functionalities for biomedical applications, including targeted drug delivery and hyperthermia therapies.
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Abstract Number: ANPA2025-N00067 Presenting Author: Shivaraju Chandrappa Co-Authors: No Presenter's Affiliation: UPR university Title: Electrolyte additive for Mg-ion batteries Location: Virtual Presentation Show/Hide Abstract The unstable solid-electrolyte interface (SEI) poses a major obstacle to the widespread use of rechargeable magnesium batteries (RMBs) as high-volumetric-capacity next-generation energy storage systems.
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Abstract Number: ANPA2025-N00041 Presenting Author: Yuwaraj K. Kshetri (Invited) Co-Authors: nan Presenter's Affiliation: Sun Moon University, Republic of Korea Title: Neutron Diffraction and Electronic Structure Investigation of Er-α-SiAlON for High-Temperature Sensing Location: In-Person Presentation, CDP Show/Hide Abstract α-SiAlON ceramics have been in use as engineering ceramics in the most arduous industrial environments such as molten metal handling, cutting tools, gas turbine engines, extrusion molds, thermocouple sheaths, protective cover for high-temperature sensors, etc., owing to their outstanding mechanical, thermal, and chemical stability. Taking advantage of the intrinsic properties of α-SiAlONs, we investigate the possibility of using the Er-doped α-SiAlON (Er-α-SiAlON) ceramic as a high-temperature sensing material via its unique near-infrared to visible upconversion property. We first use neutron diffraction and density functional theory calculations to study the electronic structure and thermodynamic stability of Er-α-SiAlON. Neutron diffraction is particularly essential in this study, as X-ray diffraction alone cannot precisely determine the atomic positions due to the similar X-ray scattering cross-sections of oxygen (O) and nitrogen (N) atoms. In contrast, neutron diffraction provides significantly different scattering cross-sections for O and N, enabling accurate crystal structure identification of SiAlON ceramics. It is found that the interstitial doping of Er stabilizes the α-SiAlON structure via chemical bonds with O-atoms with an N:O ratio of 5:2 in the seven-fold coordination sites of the Er3+ ion. Temperature-dependent upconversion emissions are then studied under 980 and 793 nm excitations over a temperature range of 298–1373 K, and the fluorescence intensity ratio (FIR) technique has been employed to investigate the temperature sensing behavior. Temperature-dependent Raman behavior is also investigated. We demonstrate that using Er-α-SiAlON as a sensing material, the limit of temperature measurement via the FIR technique can be pushed well beyond 1200 K.
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Abstract Number: ANPA2025-N00048 Presenting Author: Bed Prasad Pandey Co-Authors: Santosh Kumar Pandit; Sanju Shrestha; Om Prakash Niraula; Kavindra Kumar Kavi Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kathmandu, Nepal Title: Performance Optimization of Triple-Metal High-K Dielectric Double-Gate Tunnel Field-Effect Transistor (TFET) for Enhanced Tunneling Characteristics Location: In-Person Presentation, CDP Show/Hide Abstract Vertical Tunnel Field Effect Transistor (VTFET) is being studied, because of its extremely low of sub-threshold swing (SS) and higher current ON-OFF ratio. Hence, various physical parameters and the performances of the optimal designed the Triple Metal High-K Dielectric Double Gate Vertical Tunnel Field Effect Transistor (VTFET), prepared by using 2D simulator using HfO2 / SiO2 as a gate dielectric and substrates are investigated. The calculated I_(on )/I_off ratio and the SS are found to be 1.85x 10^13 and 15.89 mV/decade. The higher value of the current ratio and the lower SS made its application as a fast switching and low power consumable device. The studies of analog parameters such as input and output capacitances and cutoff frequencies makes its applications in many analog and digital low power applications also.
Keywords: High-K dielectric, sub-threshold swing, vertical field effect transistor, fast switching, low power consumable device.
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Abstract Number: ANPA2025-N00061 Presenting Author: Pramod Kumar Thakur Co-Authors: Gopi Chandra Kaphle; Hari Prasad Lamichhane; Hari Shankar Mallik Presenter's Affiliation: Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu Title: Stabilities, properties and applications of Janus TaSeS 2D monolayer material Location: In-Person Presentation, CDP Show/Hide Abstract Janus 2D transition-metal dichalcogenide TaSeS monolayer exhibits a stable hexagonal crystal structure with lattice parameter 6.35 Ã… and negative values of cohesive and formation energies and positive distribution of frequencies obtained from phonon dispersion relation within the brillouin zone limit confirm its chemical and dynamical stability. All the calculations were performed through density functional theory based full potential plane-wave code within the generalized gradient approximation (GGA). The mechanical properties show its stability which is varied with the uniaxial and biaxial strain for elastic to plastic variation of the material. The electronic, magnetic, thermal and optical properties of the material show its prosing applications in the field of piezoelectric devices, field-effect transistors (FETs), optoelectronics, and spintronics devices.
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Abstract Number: ANPA2025-N00060 Presenting Author: Krishna Prasad Chapai Co-Authors: Durga Paudyal Presenter's Affiliation: Mid-West University,Surkhet,Nepal Title: Structural and Electronic Properties in Doped VCl3 Monolayer : A Density Functional Study Location: In-Person Presentation, CDP Show/Hide Abstract Two dimensional transition metal trihalides are van dar Waals (vdW) crystal which are becoming field of interest due to their intrinsic ferromagnetism and anisotropic feature down to monolayer limit. The exfoliated 3d-transition metal trihalides from its bulk counterpart has got immense interest due to its peculiar properties useful for the spintronic and memory storage applications. We report the exciting properties for pristine and 3d-TM doped VCl3 layered materials using density functional theory approach. The pristine VCl3 monolayer is found to be stable in P3 structure whose chemical stability is confirmed by negative value of cohesive and formation energy. The pristine and 3d -TM ( Cr, Ti ) doped VCl3 are found to be ferromagnetically stable in ground state. We found 2D-VCl3 as intrinsic Dirac Half Metal (DHM) in one spin channel which is immensely useful for spin current generation. Our result reveals that doping of 3d-TM ( Cr,Ti) on pristine VCl3 affects electronic and magnetic properties by altering electronic structure from DHM to semiconducting or half metallic state. The study highlights the doped structure possessing the tunable band gap at monolayer scale and its potential application for spintronics through dopant engineering.
Keywords: 2D transition metal trihalides, anisotropy, electronic properties, Dirac Half Metal, Spintronics.
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Abstract Number: ANPA2025-N00044 Presenting Author: Saroj Kafle Co-Authors: nan Presenter's Affiliation: Tribhuvan University Title: Investigation of optical and electrical properties of fluorine doped ZnO Thin films prepared by spray pyrolysis Location: In-Person Presentation, CDP Show/Hide Abstract This research project investigates the optical and electrical properties of fluorine-doped ZnO (F-
ZnO) thin films deposited on FTO-coated glass substrates using the spray pyrolysis technique.
ZnO films with a fluorine doping concentration of 15% were synthesized at approximately 400°C
from a 0.1 M precursor solution. Band gap energies decreased from 3.27 eV for undoped ZnO
to 3.15 eV for an 8-layer doped film, as determined using UV-Vis spectroscopy and Tauc plots.
Electrical characterization, performed using an LCR meter, revealed Nyquist plots with semicircular
patterns for all layers, indicating impedance behavior dominated by single relaxation processes. As
the number of layers increased from 2 to 8, bulk resistance (ð‘…2) consistently decreased (e.g., from
287.46 Ω for 2 layers to 76.61 Ω for 8 layers ), while capacitance (ð¶1) slightly increased, confirming
improved electrical conductivity. The equivalent circuit model extracted parameters, including ð‘…1,
ð‘…2 , and ð¶1, focusing on the efficient charge transport and storage properties of these films. These
results demonstrate that increasing the thickness of fluorine-doped ZnO films significantly enhances
their optical and electrical properties, making them highly suitable for applications such as solar
cells and sensors.
Keywords: ZnO thin film, Fluorine-doped ZnO, Spray pyrolysis, Nyquist plot, Optical band gap,
Electrical conductivity
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Abstract Number: ANPA2025-N00043 Presenting Author: Sarita Regmi Co-Authors: Sandip Kumar Dangi; Dinesh Kumar Chaudhary; Pitamber shrestha Presenter's Affiliation: Amrit Campus Title: OPTICAL AND ELECTROCHEMICAL PROPERTIES OF Co3O4 FILM Location: In-Person Presentation, CDP Show/Hide Abstract Cobalt oxide films have gained substantial research effort because of their electronic and optical properties in diverse fields, such as agriculture, industry, and energy storage. Herein, cobalt oxide (Co3O4) films on a fluorine-doped tin oxide glass substrate were synthesized by the spray pyrolysis technique and annealed in an air atmosphere at 350 ºC for 2 hours. The different layers of cobalt oxide films were prepared on an FTO-coated glass substrate, and the films formed were blackish-white. The prepared films were characterized using FTIR spectroscopy, UV-visible spectroscopy, and impedance spectroscopy. The FTIR spectra showed the two stretching bands Co(III)-O and Co(II)-O, which confirms the material composition of Co3O4. The optical measurements demonstrated that increasing the layers of cobalt oxide films, the band gap energy decreases. The thickest layer (Layer 9) showed the minimum band gap of about 2.21 eV. The impedance measurement was carried out from the high to low-frequency range, where the obtained impedance spectrum revealed enhanced conductivity and reduced grain boundary resistance with increasing film thickness, which may be due to increased mobility of charge carriers and reduced grain size. These results showed the tunable optical properties and enhanced charge transfer, highlighting the potential application for optoelectronic devices and supercapacitor applications.
Keywords: Cobalt oxide, Impedance, Thin film, Spray pyrolysis, Band gap
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Abstract Number: ANPA2025-N00059 Presenting Author: Bimala Debi Subedi Co-Authors: GAMBHIR KHAN THAKURI 7; LEELA PRADHAN JOSHI Presenter's Affiliation: Atmospheric and Material Science Research Centre, Amrit Campus, Tribhuvan University, Kathmandu, Nepal bDepartment of Physics, Prithvi Narayan Campus, Tribhuvan University, Pokhara, Nepal. Title: Electrochemical performance of activated carbon derived from waste wood of Alnus nepalensis for supercapacitor application Location: In-Person Presentation, CDP Show/Hide Abstract The growing demand for sustainable energy storage solutions has accelerated the development of advanced energy storage technologies. Traditional carbon materials sourced from fossil fuels present challenges such as high costs, complex processing, and potential environmental risks. In contrast, biomass-derived activated carbon has emerged as a highly promising alternative, offering advantages like natural abundance, high carbon content, and straightforward processing with minimal toxicity. This study outlines the production of activated carbon from waste wood of Alnus nepalensis through a series of processes, including activation using zinc chloride as the activating agent, followed by pre-carbonization and carbonization at 600°C in a tube furnace under a continuous flow of N₂ gas. The activated carbon was analyzed using various methods, including FTIR testing, while its electrochemical performance was evaluated through CV, GCD, EIS, and CV retention tests. These tests were conducted using a three-electrode arrangement with different reference electrodes (Hg/HgO, Ag/AgCl) and 6M KOH aqueous electrolyte solution. As a supercapacitor electrode material, AC exhibited a specific capacitance of 186.03 F/g at a current density of 1A/g, an energy density of 6.46 Wh/kg, and a power density of 124.99 W/kg. It demonstrated capacitance retention of 64.5% after 1,000 charge–discharge cycles at a current density of 1 A/g using an Hg/HgO reference electrode in a 6M KOH electrolyte. These results provide valuable insights into the development and electrochemical analysis of eco-friendly biomass-derived porous carbon, highlighting its potential as a supercapacitor electrode material.
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Abstract Number: ANPA2025-N00047 Presenting Author: Sandip Kumar Dangi Co-Authors: Sarita Regmi; Dinesh Kumar Chaudhary; Pitamber Shrestha Presenter's Affiliation: Amrit Campus, Lainchaur, Kathmandu Title: Electro-Chemical and Optical Characterization of SnO2 Film Location: In-Person Presentation, CDP Show/Hide Abstract Metal oxide thin films have gained considerable attention due to their diverse applications in agriculture, medicine, industry, and advanced technologies. Among these, SnOâ‚‚ thin films have emerged as promising materials for optoelectronic applications. In our study, SnOâ‚‚ thin films were synthesized on fluorine-doped tin oxide (FTO) substrates using a spin-coating technique, followed by annealing at 400°C to enhance crystallinity. The prepared samples were analyzed by various techniques such as FTIR spectroscopy, UV-Vis spectroscopy and Impedance spectroscopy. FTIR analysis confirmed the formation of the SnOâ‚‚ lattice with distinctive peaks at 516 cmâ»Â¹ and 754 cmâ»Â¹. UV–Vis revealed that optical transmittance decreased with increasing film thickness, while the optical band gap increased slightly from 3.45 eV to 3.55 eV. Concurrently, a decrease in Urbach energy from 0.2154 eV to 0.1619 eV suggested a reduction in defect density. The refractive index, determined via the Swanepoel method, stabilized at approximately 1.83, indicating enhanced densification and reduced porosity. Impedance spectrum showed that although the series resistance remained relatively constant, the charge transfer resistance increased and capacitance decreased with film thickness, indicating the critical role of film thickness in tuning the optical and electrical properties of SnOâ‚‚ thin films, paving the way for their optimized use in optoelectronic applications. Keywords: Tin oxide, Spin coating, Band-gap, Impedance spectrum, FTIR analysis.
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Abstract Number: ANPA2025-N00042 Presenting Author: Kaushal Pyakurel Co-Authors: Leela Pradhan Joshi Presenter's Affiliation: Central Department of Physics, TU Title: Synthesis and Electrochemical Performance of Activated Carbon from Lapsi Seed Biomass for Supercapacitor Application Location: In-Person Presentation, CDP Show/Hide Abstract The conversion of biomass waste into porous carbon for supercapacitor electrode application represents a promising
approach due to the low cost, abundance of raw materials, and environmental advantages. In this study, activated carbon(AC) was
synthesized from Lapsi (Choerospondias axillaris) seed biomass by chemical activation method with zinc chloride (ZnCl2) fol-
lowed by carbonization in the tubular furnace at 850 °C under continuous nitrogen flow of 100 cc/min for 4 hours. Electrochemical
characteristics of the AC electrode was studied in a three-electrode system with a potentiostat device through cyclic voltammetry
(CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS). The electrochemical parameters
such as specific capacitance, stability, and impedance are evaluated. The electrode exhibited a specific capacitance of 71.95 F/g
at a current density of 1 A/g and maintained 95.71% capacitance retention over 5000 cycles, demonstrating good electrochemical performance.
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Abstract Number: ANPA2025-N00062 Presenting Author: Ambika Shahi Co-Authors: nan Presenter's Affiliation: Central Department of Physics, Tribhuvan University Title: To investigate the Structural, Electronic and Magnetic properties of CrGa2S4 Location: In-Person Presentation, CDP Show/Hide Abstract Condensed matter physics, as a field, integrates various aspects of natural science, including theoretical, experimental, and computational approaches. It enables the exploration and understanding of novel materials across different length scales, from the atomic-microscopic levels to macroscopic phenomena. In this work, the Transition Metal (TM)-based ternary chalcogenide CrGa2S4 compound is a novel material that exhibits intriguing structural, electronic, and magnetic properties in both bulk and 1-structural layer, adopting an α-FeGa2S4-1T type phase. It crystallizes in the P-3m1 space group with lattice parameters a = 3.60 ˚A and c = 11.94 ˚A. First-principles calculations based on density functional theory were performed using the FPLO code with GGA, GGA+U, and GGA+SOC functionals. To achieve accurate band gap predictions, GGA+mBJ and GGA+mBJ+SOC were employed. The bulk structure exhibits a ferromagnetic ground state with half-metallic behavior, while the 1-structural layer undergoes a transition to a semiconducting state with an indirect band gap of 0.72 eV. The magnetocrystalline anisotropy energy calculations reveal an easy axis along [001] for the bulk and [100] for the 1-structural layer. This study emphasizes the phenomenal influence that dimensionality reduction on the electronic structure and offers insight into the tunability of electronic and magnetic characteristics. These findings pave the way for potential applications in electronic storage devices, particularly in spintronics.
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Abstract Number: ANPA2025-N00050 Presenting Author: Prashnna Gyawali Co-Authors: Chowdhury Mohammad Abid Rahman; Aldo H. Romero Presenter's Affiliation: West Virginia University Title: Supervised Pretraining for Material Property Prediction Location: In-Person Presentation, Fairmont Show/Hide Abstract Accurate prediction of material properties facilitates the discovery of novel materials with tailored functionalities. Deep learning models have recently shown superior accuracy and flexibility in capturing structure-property relationships. However, these models often rely on supervised learning, which requires large, well-annotated datasets—an expensive and time-consuming process. Self-supervised learning (SSL) offers a promising alternative by pretraining on large, unlabeled datasets to develop foundation models that can be fine-tuned for material property prediction. In this work, we propose supervised pretraining, where available class information serves as surrogate labels to guide learning, even when downstream tasks involve unrelated material properties. We evaluate this strategy on two state-of-the-art SSL models and introduce a novel framework for supervised pretraining. To further enhance representation learning, we propose a graph-based augmentation technique that injects noise to improve robustness without structurally deforming material graphs.
The resulting foundation models are fine-tuned for six challenging material property predictions, achieving significant performance gains over baselines, ranging from 2\% to 6.67\% improvement in mean absolute error (MAE)—and establishing a new benchmark in material property prediction. This study represents the first exploration of supervised pertaining with surrogate labels in material property prediction, advancing methodology and application in the field.
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Abstract Number: ANPA2025-N00046 Presenting Author: Basu Dev Oli Co-Authors: Qiang Zou; Subhasish Mandal; Lian Li Presenter's Affiliation: Department of Physics and Astronomy, West Virginia University Title: Engineering superconductivity in Single-layer FeSe through Substrate Surface Terminations Location: In-Person Presentation, Fairmont Show/Hide Abstract The discovery of high-temperature superconductivity in single-layer FeSe films grown on (001) SrTiO3 (STO) substrates has sparked extensive research into the underlying mechanisms. Most studies have focused on FeSe films grown on TiO2-terminated STO substrates, while several models have been proposed to explain the enhanced superconductivity. In this work, we synthesized FeSe films on both TiO2- and SrO-terminated STO substrates by molecular beam epitaxy and compared their superconducting properties by scanning tunneling microscopy/spectroscopy (STM/STS). dI/dV tunneling spectroscopy reveals a larger superconducting gap of ï„ = 17 meV on FeSe/TiO2 regions, while a smaller gap of ï„ = 11 meV on FeSe/SrO. By comparing experimental findings with dynamical mean field theory calculations, our results indicate optimal electron correlations at the FeSe-TiO2 interface for enhancing superconductivity in single-layer FeSe.
This work is supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering (DE-SC0017632).
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Abstract Number: ANPA2025-N00052 Presenting Author: Dinesh Thapa Co-Authors: Sumon Hati; Rajesh Sardar; Svetlana Kilina Presenter's Affiliation: Thomas More University Title: Ultralow work function modulation via interfacial dipole formation in gold metal organic framework Location: In-Person Presentation, Fairmont Show/Hide Abstract The chemistry of the gold metal organic frameworks (MOFs) has increased considerably in recent decades because of their structural diversity, chemical versatility, and selective adsorptions to apply in numerous fields of catalysis, sensing, gas sorption, organic electrodes, and biomedicine. In this work, we perform the theoretical and experimental tailoring of the work function of the gold (Au) (111) surface adsorbed with various organic molecules together with the determination of dipole moment and charge transfer along the interfaces. We implemented the state-of-art spin polarized density functional theory (DFT) to modulate the work function of the organically modified Au (111) surface manifested by a strong dipole formation at the interfaces. The substrate work function is found to be lowered by ~0.7-0.9 eV compared to pristine Au (111) surface due to subtle interplay between Pauli’s push back effect and the substantial transfer of electrons (~1.0e-1.7e) from the Au metal to the adsorbed organic molecule. The ultralow work function thus obtained is further supported by the formation of interfacial dipole pointing towards the metal, with dipole moment value as large as 3.6 Debye (in linear chain of benzene rings) to 4.9 Debye (in fused benzene rings). Our computational modeling and experimental observations provide an invaluable tool to actually understand the detailed mechanism behind the observed work function reduction via the ever-existent Pauli repulsion. Here, the interacting metal electrons are pushed back into the metal due to Coulomb repulsion from the electrons localized at the adsorbate, thereby lowering the work function. Owing to the reduced work function value and quantized charge separations at the interface, our proposed MOFs hold particularly high promise for using as electron injecting electrodes into organic electronic devices.
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