Condensed Matter Physics Commons^™

Developing A Workforce To Build A Star On Earth, Vola Andrianarijaona, Angelina Castillo, Sean Walters

Campus Research Month

This study is meant to help understand why fusion has remained "30 years away" for decades and why that may finally be changing.We see nuclear fusion not merely as a physics phenomenon, but as a complex engineering challenge requiring coordination across different disciplines, including physics, materials science, electrical and mechanical engineering, systems engineering, robotics, and computer science, etc. Indeed, nuclear fusion is not just about "making atoms fuse"—it's about controlling, powering, measuring, and stabilizing one of the most extreme environments humans have ever built. Advances in superconducting magnets, new materials are bringing fusion closer to reality than ever before, and …

Harnessing Wavefront Shaping Control For Sensing Applications, Pablo Jara

Miners Solving for Tomorrow Research Conference

Diffuse optical tomography (DOT) and functional near-infrared spectroscopy (fNIRS) enable deep, non-invasive sensing in biological tissue but are fundamentally limited by the photon budget - most injected light is lost to scattering before reaching the detector. Wavefront shaping (WFS) can enhance signal strength inside scattering media via interference, but the conventional diffusion-based sensitivity model breaks down under coherent illumination. We develop a microscopic theory of optical sensitivity that captures interference effects neglected by diffusion theory. We prove analytically that the microscopic and diffusive descriptions coincide under random illumination and identify WFS strategies that enhance sensitivity beyond this limit. The maximum …

Optimization Of Niobium Film For Particle Accelerators And Quantum Applications, Bektur Abdisatarov

Electrical & Computer Engineering Theses & Dissertations

Niobium (Nb) films play a central role in superconducting technologies used in particle accelerators and superconducting quantum circuits. Optimizing the physical properties of Nb films is therefore critical for improving both radiofrequency (RF) performance in superconducting radiofrequency (SRF) cavities and coherence in superconducting qubits. This thesis investigates the relationship between Nb film microstructure, impurity content, and electromagnetic response across these two application domains.

For particle accelerator applications, we studied Nb films deposited using high-power impulse magnetron sputtering (HiPIMS) with DC bias onto a 1.3 GHz elliptical SRF cavity. Nb film cavities exhibit a pronounced medium-field Q-slope, limiting their achievable accelerating …

Fabrication And Analysis Of Bi₂O₃/Si Heterojunction For Solar Cell Applications, Maher Khaleel Ibrahim, Assel Mustafa Abdul Majeed, Randa Kamel Husain, Jamal M. Rzaij

Al-Bahir

Bismuth oxide (Bi₂O₃) nanoparticles were synthesized via a green route and integrated into Bi₂O₃/Si heterojunction solar cells. Structural analysis confirmed the monoclinic α-Bi₂O₃ phase with a nanoscale crystallite size, while SEM revealed a uniform morphology. Optical studies showed a direct band gap suitable for absorbing visible light. Photoluminescence spectra exhibited dual emissions at 498 nm and 250 nm, attributed to defect states and quantum confinement, highlighting the dual role of Bi₂O₃ as both absorber and transparent window layer. Electrical characterization under dark conditions demonstrated rectifying diode behavior, confirming the formation of a junction. Capacitance–voltage analysis yielded a built-in potential of …

Extension Of The Local Vibrational Mode Theory To Periodic Systems, Filippo Bodo

Chemistry Theses and Dissertations

Over the years, vibrational spectroscopy was used to gain a deeper understanding of the electronic structure and the chemical bond in both molecular and periodic systems. In this framework, the Local Vibrational Mode Theory (LVMT), as first introduced by Konkoli and Cremer in 1998, provides a unique tool to quantify the strength of a chemical bond, and better interpret the molecular vibrational spectra, thanks to the adiabatic force constants ($k^a$) and the composition of normal modes (CNM). While LVMT was originally developed for molecular systems, its application to periodic solids has remained limited. This thesis presents a complete and systematic …

Characterization Of Physical And Structural Properties In A Quaternary Li2o-B2o3-Bi2o3-V2o5 Glass System, Alan Ikram Ahmed, Mowfaq Jalil Ahmed

Polytechnic Journal

Borate-based glasses modified with alkali oxides are of considerable interest due to their tunable structural and optical properties, which are important for optical and energy storage applications. In this work, glasses with a novel nominal composition of xLi2O-(75-x) B2O3—20Bi2O3—5V2O5, in which (x ¼ 5, 10, 15, 20, 25 mol %) were produced using the traditional melt-quenching technique to investigate the effect of substituting the glass former B2O3 with the modifier Li2O. The structural and optical properties were examined by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and UV—visible spectroscopy. The XRD analysis confirms the amorphous nature of the samples produced. …

Electronic Transport In Twisted Bilayer Tungsten Diselenides, Walid Zaher

Theses and Dissertations

This thesis investigates density waves (DWs) in twisted bilayer tungsten diselenide (tWSe₂) using a mean field approximation, with a focus on electron-electron interactions, and the system’s free energy at zero temperature. For the mean field approximation, the study initially employed same-spin nesting vectors, which were found insufficient to induce DWs formation. In contrast, when opposite-spin nesting vectors were used, DWs emerged, indicating that these vectors can support DWs formation. The plots were produced under perfect nesting conditions, where van Hove singularities (VHS) occur. At zero temperature, perfect nesting provides a complete picture of the upper limit of DWs formation, as …

Ultrafast Terahertz Spectroscopy And The Suppression Of Superconductivity In Strained Iron Selenide Below 1 Kelvin, Tracy Glen Hastings

ETDs from 2020-2029

We report on terahertz time-domain spectroscopy measurements of iron selenide thin films of various thicknesses grown on a magnesium oxide substrate, focusing on the frequency-dependent complex conductivity in the range of 0.25 - 7 THz. By an- alyzing films with and without an approximately 100 nm thick Se capping layer, we examined the role of oxidation in the suppression of superconductivity. X-ray photo- electron spectroscopy data confirmed that oxidation was effectively mitigated, yet the films exhibited insulating behavior down to 200 mK, a temperature range that has not been extensively studied in this system. Our results indicate that the suppression …

Enhanced Superconductivity And Vortex Dynamics In Quasi-1d Tas2 Nanowires, Mathew Pollard, Visakha Ho, Clarissa Wisner, Eric W. Bohannan, Yew San Hor

Chemistry Faculty Research & Creative Works

We report the synthesis of high-quality 2H-TaS₂ nanowires via a controlled two-step conversion process from TaS₃ precursors, achieving robust superconductivity with a transition temperature T c ≈ 3.6K, which is significantly higher than bulk 2H-TaS₂ (T c ≈ 0.8K). Structural and compositional analyses confirm phase purity and preserved one-dimensional morphology, while magneto transport measurements reveal an enhanced upper critical field μ 0 H c2 (2K)≈5 T, far exceeding the bulk value (_μ0H_c2 (0)≈1.17T), attributed to dimensional confinement and suppression of charge-density wave order. Magnetic characterization demonstrates complex vortex dynamics, including flux jumps and a …

Magnetic Anisotropy Engineering In Rare-Earth-Free Iron-Based Magnetic Materials, Pramanand Joshi

Physics Dissertations - Archive

The development of high-performance, rare-earth-free hard magnetic materials is critical for next-generation energy, information, and spin-based technologies. This dissertation investigates structure-property relationships in iron-based magnetic systems, including iron carbides, Fe-Co-B boride alloys, hexaferrites, and FeCo nanostructures, synthesized via chemical and metallurgical routes. Through controlled synthesis and comprehensive structural and magnetic characterization, this work demonstrates that magnetic anisotropy, coercivity, and thermal stability can be systematically controlled through morphology design, compositional tuning, microstructural refinement, and interparticle interaction modulation.

Morphology-driven enhancement of magnetic properties, particularly coercivity and blocking temperature, is established in phase-pure Fe₅C₂ nanostructures. By precisely controlling particle geometry, …

Applications Of Doppler Broadening Spectroscopy For The Characterization Of The Surface And Near Surface Of Two-Dimensional Heterostructures, Hany M. Mahdy

Physics Dissertations

This dissertation describes experiments and the analysis of Doppler broadening spectroscopy applied to metal surfaces (Cu, Ag, Au), graphene/Cu heterostructures, and SiGe heterostructures, with particular emphasis on the development of new approaches for extracting quantitative information from annihilation spectra.

The first part establishes the capability of Doppler broadening spectroscopy, particularly coincidence Doppler broadening (CDB), as a surface-sensitive technique. Measurements on clean and adsorbate-covered Cu, Ag, and Au surfaces demonstrate that Doppler-broadened annihilation spectra retain element-specific signatures from the topmost atomic layer. New analysis methods based on ratio-curve modeling enable identification and quantification of sub-monolayer adsorbates, including sulfur, oxygen, selenium, and …

Ultrafast Vibrational Dynamics In Important Wide-Bandgap Semiconductors, Dielectrics And Energetic Materials, Dinusha Madushanka Senarathna

Open Access Dissertations

This dissertation applies time-resolved coherent anti-Stokes Raman scattering (tr-CARS), to measure ultrafast vibrational dynamics in technologically important solid-state and van der Waals molecular systems. The central goal is to use time-domain Raman methods to resolve mode-specific phonon and vibrational dephasing processes with high temporal precision, high spectral selectivity, and sufficient experimental flexibility to probe materials ranging from wide-bandgap semiconductors and oxide crystals to energetic molecular crystals. Across the work, I show that carefully designed tr-CARS measurements can access vibrational lifetimes from hundreds of femtoseconds to several picoseconds, enabling direct observation of decay pathways, relaxation mechanisms, and dispersion effects that shape …

Harnessing Coherent-Wave Control For Sensing Applications In Scattering Media, Pablo Xavier Jara Palacios

Doctoral Dissertations

"Diffuse electromagnetic waves are widely used for non-invasive sensing and imaging in complex scattering media such as biological tissues. A fundamental limitation of such techniques is the scarcity of detected photons: as the source-detector separation increases to access deeper regions of the medium, the signal strength decays rapidly, leading to poor signal-to-noise ratio and limited sensitivity. This dissertation addresses this challenge through a combination of theory and computation.

We show that coherent control of the incident optical wavefront can compensate for the scarcity of detected photons that limits conventional diffuse optical imaging, typically performed in the near-infrared spectral region. By …

Nanostructured Cathode Catalysts For Aem Electrolysis: From Catalyst Design To Degradation And Hydrogen Dynamics, Yamini Kumaran

Electronic Theses & Dissertations (2024 - present)

Anion exchange membrane water electrolysis (AEMWE) presents a promising pathway toward cost-effective and sustainable hydrogen production by integrating the chemical robustness of alkaline systems with the compact, zero-gap design of proton exchange membrane electrolyzers. However, the widespread implementation of AEMWE is limited by the availability of highly active and durable platinum-group-metal (PGM)-free catalysts and by an incomplete understanding of their degradation behavior under realistic operating conditions.

This dissertation focuses on the development, characterization, and mechanistic investigation of nanostructured MoNi₄–MoO₂-based electrodes for efficient and stable hydrogen generation under alkaline and membrane-integrated environments. MoNi₄–MoO₂ nanorods …

Quantum Critical Behavior Of Diluted Quasi-One-Dimensional Ising Chains, Logan Sowadski, Thomas Vojta

Physics Faculty Research & Creative Works

(Formula presented.) (Formula presented.) is a unique magnetic material. It features bulk 3D magnetic order at low temperatures, but its quantum critical behavior in a magnetic field is well described by the 1D transverse-field Ising universality class. This behavior is facilitated by the structural arrangement of magnetic (Formula presented.) ions in nearly isolated zig-zag chains. In this work, we investigate the effect of random site dilution on the critical properties of such a quasi-1D quantum Ising system. To this end, we introduce an anisotropic site-diluted 3D transverse-field Ising model. We find that site dilution leads to unconventional activated scaling behavior …

Emergent Spin Fluctuation And Structural Metastability In Self-Intercalated Cr1+Xte2 Compounds, Clayton Conner, Ali Sarikhani, Theo Volz, Mathew Pollard, Mitchel Vaninger, Xiaoqing He, Steven Kelley, Jacob Cook, Avinash Sah, John Clark, Hunter Lucker, Cheng Zhang, Paul Miceli, Yew San Hor

Physics Faculty Research & Creative Works

Intercalated van der Waals (vdW) magnetic materials host unique magnetic properties due to the interplay of competing interlayer and intralayer exchange couplings, which depend on the intercalant concentration within the van der Waals gaps. Magnetic vdW compound chromium telluride, (Formula presented.), has demonstrated rich magnetic phases at various Cr concentrations, such as the coexistence of ferromagnetic and antiferromagnetic phases in (Formula presented.) (equivalently, (Formula presented.)). The compound is created by intercalating 0.25 Cr atom per unit cell within the van der Waals gaps of (Formula presented.). In this work, we report a notably increased Curie Temperature and an emergent in-plane …

Growth And Dielectric Characterization Of Epitaxial Sr1-Xmgxtio3 Thin Films, Richard Badu

UNF Graduate Theses and Dissertations

Complex oxide materials with ferroelectric ground states remain promising candi dates for next-generation high-capacitance and nonlinear microelectronic applica tions. One of those materials is SrTiO3 (STO). However, STO is an incipient fer roelectric with anomalously high dielectric permittivity at low temperatures. STO crystals possess a highly polarizable lattice that is sensitive to even small amounts of impurities. Substituting Mg into the STO matrix is predicted to induce a corre lation between ferroelectric and relaxor behavior. In this thesis, we demonstrated the growth of a series of epitaxial STO and Sr1-xMgxTiO3 thin films using molec ular beam epitaxy. The surface evolution …

First-Principles Investigation Of Quasi-One-Dimensional Van Der Waals Magnets For Advancing Low-Dimensional Spintronics, Alyssa Horne

Dissertations, Master's Theses and Master's Reports

Van der Waals (vdW) magnets have been of great interest for advancing low- dimensional spintronics. A notable example is the quasi-one-dimensional (Q1D) vdW CrSbSe₃, as it is composed of individual one-dimensional units that are held together by the vdW forces. Finding other Q1D vdW magnets that exhibit non-metallic behavior together with long range ferromagnetic ordering is critical in developing next generation spintronics. Here in, using first-principles density functional theory (DFT), we investigate the compositional effects on electronic and magnetic behavior of Cr_1–xMn_xSbSe₃ (x = 0, 0.5, 1). When 50% of Cr is replaced …

Investigating The Effects Of Pressure On Fe And Co Intercalated 2h-Tas2 Through First-Principle Calculations, Ronald E. Putnam Jr.

UNF Graduate Theses and Dissertations

Using first-principles methods, we investigate the effects of applied isotropic pressure on the electronic and magnetic properties of intercalated Fe1/3TaS2 and Co1/3TaS2. Fe1/3TaS2 has been shown to be a ferromagnet that undergoes structural and magnetic phase transitions under applied pressure. The magnetic phase transitions are observed to be linked to the structural shift, and a mixture of magnetic phase states is present between 3 GPa and 6 GPa. Co1/3TaS2 was found to be antiferromagnetic, as confirmed by experimental work. One- and two-unit-cell systems of Co1/3TaS2 are analyzed, both showing band splitting that disappears under pressure. The application of pressure forces …

Investigating A Nanoparticle-Assisted Approach For Localized Strain Engineering In Two-Dimensional Materials, Skye Martichuski

Honors Theses and Capstones

This work investigated a fabrication strategy for inducing localized nanoscale deformation and strain in transferred MoS2 flakes using gold nanoparticle-coated substrates as a potential platform for strain engineering in two-dimensional materials. Substrate type, nanoparticle concentration, drying conditions, cleaning procedures, and flake transfer methods were investigated using optical microscopy and atomic force microscopy (AFM). Au-coated SiO2 substrates produced improved nanoparticle coverage compared to bare SiO2, while passive air drying yielded the most favorable nanoparticle distributions. Salt crystals introduced during passive drying were successfully removed with a gentle deionized water rinse, and a 50% diluted gold nanoparticle suspension provided improved particle spacing …

Charge Transport Modeling Of Multifunctional Molecular Transistors, Romena Akter

Graduate Studies Theses and Dissertations 2026

Distinguishing between the current–voltage characteristic curves associated with different transport mechanisms in a molecular electronic device and an artifact arising from device-level disorder is a central challenge in the study of molecular electronics. Characterizing these mechanisms and connecting them qualitatively to molecular-level orbital alignment, electrode coupling, voltage division, energetic disorder, and reorganization energy requires not only experimental data but also a rigorous theoretical framework for extracting physically meaningful parameters from measured transfer characteristics. This dissertation addresses this challenge in Chapters 2, 3, and 4 by developing and applying four complementary transport models —Simmons tunneling, single-level Landauer, Marcus hopping, and McConnell …

Investigation Of Exotic Phenomena In Topological Quantum Materials, Iftakhar Bin Elius

Graduate Studies Theses and Dissertations 2026

he First Quantum Revolution established quantum mechanics as the foundation of modern physics, enabling transformative technologies such as semiconductors, lasers, and transistors through prin-ciples of quantization, wave-particle duality, and uncertainty. The ongoing Second Quantum Rev-olution harnesses entanglement, superposition, and coherence to advance quantum computation, communication, simulation, and sensing. Central to this endeavor is the study of quantum mate-rials hosting novel electronic structures and emergent phases, including topological insulators and Dirac, Weyl, and nodal-line semimetals. In this thesis, using angle-resolved photoemission spec-troscopy (ARPES), transport measurements, and density functional theory (DFT) calculations, we investigate three classes of materials: (i) magnetic topological semimetals, …