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The central focus of this thesis is a study of materials with competing magnetic interactions and understanding how these interactions affect the overall magnetic behavior of solids. Understanding the fundamental factors that can be used...
We studied the relationship between superconductivity and magnetism in the heavy fermion CeCoIn5 using a miniature cell in a top loading dilution refrigerator with a 16 T magnet (XCF – Xtreme Conditions Fridge). The construction and...
Nb 3 Sn conductors are important candidates for high-field magnet applications for Future Protonor Muon Colliders, and they continue to be widely used for many laboratory and NMR magnets. However, the critical current density, J c, of...
One of the biggest roadblocks currently in the way of large scale quantum computation is the limited relaxation times of the current state of the art quantum computers. This limitation is due to the use of superconducting qubits, which...
This dissertation focuses on the transport properties of the high-temperature superconductor LSCO in high magnetic fields, particularly the longitudinal magnetoresistance around optimum doping. In this region of the phase diagram the...
This thesis studied the electronic structure at the Fermi level and the topological character of topological semimetals via torque magnetometry. Torque magnetometry measures the anisotropic magnetization of the sample in a tilted...
In this thesis we have combined the idea of cluster expansion and path integration to develop the quantum version of cluster and virial expansion. We derive a diagrammatic series expansion for different thermodynamic quantities like free...
This dissertation is a theoretical and computational examination of electronic properties of topological materials, such as topological insulators and Weyl semimetals. Our work is motivated by various experimental observations and...
The heavy fermion intermetallic compound URu₂Si₂ continues to attract attention owing mainly to the occurrence of an unknown ordered state at T₀ ~ 17.5 K that is referred to as "hidden order" (HO). HO remains enigmatic, despite more than...
We report the synthesis and characterization for two single crystalline lanthenide-host compound Sm$_{6}$T$_{4}$Al$_{43}$ (T = Mo and W), that form in the hexagonal Ho$_{6}$Mo$_{4}$Al$_{43}$ prototype. The Sm ions reside within T/Al...
This dissertation details the use of 93Nb (γ = 10.405 MHz/T, I = 9/2) and 77Se (γ = 8.13 MHz/T, I = 1/2) nuclear magnetic resonance (NMR) to investigate the phase transitions of the layered transition metal dichalcogenide (TMD) niobium...
The understanding of magnetic materials has become crucial to both fundamental physics and technological advancement. Particularly, the interplay between magnetic and electronic properties has given rise to such novel physics as high...
Magnetic two-dimensional (2D) materials, proposed to exhibit non-trivial electronic topology, have been discovered recently. In particular, a potential for devices based on van der Waals (vdW) ferromagnetic heterostructures was...
The dissertation presents the recent development of the 3rd generation femtosecond electron diffractometer in Professor Jim Cao's group. Two techniques, femtosecond electron shadow imaging and deflectometry (FESID) and femtosecond...
We examine two wave function optimization methods for producing the ground state. The first is a novel method for optimizing the location of the nodes of the fermion ground-state using a combination of diffusion Monte Carlo (DMC) and...
The Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity is one of the jewels of 20th century physics. In this theory, the superconducting state of a metal is understood in terms of the formation of electron pairs which condense...
The understanding of the electronic systems of materials has not been only the essential, but the driving force, behind the progress of technology for over 100 years. This year marks the 60th anniversary of the revolutionary Bardeen...
High temperature superconductors (HTS) allow for the construction of magnets generating fields of more than 30 T, enabling the investigation of new phenomena in condensed matter science and high energy physics. High field magnets store...
This dissertation explores several aspects of microwave spectroscopy of two-dimensional electron systems (2DES), motivated by the microwave signatures of Wigner crystal phases that can exist in these systems. The spectroscopy is carried...
This dissertation is a theoretical and computational examination of structural, electronic and magnetic properties of complex transition metal oxide structures. Our work is motivated by experimental observations that transition metal...
Topological phases of matter and the phase transitions between them have been the focus of much recent theoretical and experimental interest. In this thesis, we firstly study a type of topological phase transitions between quantum Hall...
This dissertation presents the recent developments and experiments performed using the third generation femtosecond electron diffractometer in Professor Jianming Cao's group as well as experiments performed using the previous second...
Strongly correlated insulators (SCIs) are proposed as a promising material for photovoltaics because the strongly correlated \textit{d} electrons can facilitate the creation of multiple electron-hole pairs per incoming photon through a...
Doubly-connected superconducting loops are a class of superconducting devices of longstandinginterest in fundamental physics and practical applications. They have been studied since early 1960s and have received intensive recent interest...
This dissertation is focused on electrical spin injection and detection at the nanoscale dimensions that semiconductor nanowires offer. Semiconductor spintronics is the natural extension of metallic spintronics for applications in...
Strongly correlated materials manifest some of the most intriguing behaviors found in condensed matter physics. However, their understanding remains a challenge because they cannot be described using standard theoretical approaches, as...
Colloidal suspensions transform between fluid and disordered solid states when parameters such as the colloid volume fraction and the strength and nature of the colloidal interactions are varied. Seemingly subtle changes in the...
Transition metal dichalcogenides (TMDs or TMDCs) have garnered much interest recently due to their weakly layered structures, allowing for mechanical exfoliation down to a single atomic layer. As such, it is pertinent to re-examine the...
We report a study on the magnetotransport properties and on the Fermi surfaces (FS) of the ZrSi(Se, Te) semimetals. Density Functional Theory (DFT) calculations, in absence of spin orbit coupling (SOC), reveal that both the Se and the Te...
Materials that contain f-electron elements often exhibit complex phase diagrams with different phenomena including nematic electronic states, charge and spin instabilities, the breakdown of Fermi liquid behavior, and unconventional...
This body of work explores the growth and structure of two different cobalt containing compounds that may show interesting quantum spin behaviors: [(CH3)3NH]CoCl3 and BaCo2(PO4)2. In [(CH3)3NH]CoCl3, the Co ions are arranged in a chain...
Geometrically frustrated systems have garnered much interest in recent times due to the emergence of novel magnetic states in these systems that contrast traditional cooperative magnetic phenomena. The spin ice pyrochlores Ho2Ti2O7 and...
Two heavy Fermion superconducting compounds, URu₂Si₂ and PuRhIn₅, were investigated by the techniques of chemical substitution and application of high magnetic fields. These materials are particularity interesting for their unique...
We utilize crystal symmetry to develop low-energy models for a broad range of superlattice devices composed of stacks of FeSe (and similar iron-based superconductors), with the aim of engineering experimentally tunable couplings through...
This thesis is devoted to the study of magnetic properties of strongly correlated quantum matters in one and two dimensions. The study employs predominantly numerical techniques, such as Exact Diagonalization (ED), Finite Temperature...
The discovery of graphene marked a turning point in research and interest towards 2 -D materials. Among them, Transition Metal Dichalcogenides (TMDs) and Metal Monochalcogenides (MM) have seen an upturn in interest owing to their...
Despite over thirty years of research, the origin of high-temperature superconductivity remains unsolved. In these thirty years, the phase diagram for the rst-discovered high-temperature superconductors, the cuprates, has been found to...
Studying of relativistic particles in the condensed matter system became possible after a discovery of graphene in 2004. What follows from graphene was search for other materials hosting relativistic particles, such as Dirac semimetals...
Nb₂PᵪSe₅ is a high-field, anisotropic, 2-band superconductor with both electron-like and hole-like charge carriers at the Fermi level. The crystal structure is assembled such that 2D sheets of Nb₄Pd₁Se₁₀ are connected to each other by an...
This thesis presents work on optimizing a local annealing process for creating Ohmic contacts to a 2D electron gas (2DEG) within a GaAs/AlGaAs heterostructure. The optimization of this process will allow for fabrication of Hall devices...
Advances in technology require the advancement of understanding and creating new materials. Quantum materials - materials exhibiting quantum behavior- are a hot topic in condensed matter physics. Perhaps the most well known new materials...
Since the simplest case was solved exactly by Onsager in 1944, the two-dimensional Ising model has become one of the most studied models in statistical physics. Despite its simplicity, it has found applications in research ranging from...
Computational material simulation is becoming more and more important as a branch of material science. Depending on the scale of the systems, there are many simulation methods, i.e. first-principles calculation (or ab-initio), molecular...
Electrophoresis as an analytical technique has made considerable contributions to the separations and analysis of macromolecules in biology-related research. Pluronic gels, which are composed of orderly packed spherical micelles...
Semiconductor nanostructures have shown great potential for detecting and measuring chemical and biological interactions. The advantage of the electrically based schemes is real-time, label-free detection, which had been absent from...
High-purity niobium is the material of choice for making superconducting radio-frequency cavities for the modern particle accelerator. While making the cavities from the Nb sheet, it goes through a series of processes including chemical...
Quantum computing gives novel way of computing using quantum mechanics, which furthers human knowledge and has exciting applications. Quantum systems with diluted spins such as rare earth ions hosted in single crystal, molecule-based...
Semiconductor spintronics is widely regarded as a viable pathway to overcome many of the physical limitations of the present micro-electronics technology. Electrical spin injection into a semiconductor, coherent transport and...
Metal-insulator transitions (MITs) remain one of the unresolved science problems of condensed-matter physics, which are rather general and of fundamental importance. In the vicinity of the MITs, the behavior is found to be unconventional...
Understanding properties of quasiparticles in novel two-dimensional (2D) semiconductors, such as atomically thin transition metal dichalcogenides (TMDCs) and group-III metal monochalcogenides, is among the most interesting topics in...
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