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Full-Text Articles in Condensed Matter Physics
Deconfined Quantum Criticality In 2d Su(N) Magnets With Anisotropy, Jonathan D'Emidio
Deconfined Quantum Criticality In 2d Su(N) Magnets With Anisotropy, Jonathan D'Emidio
Theses and Dissertations--Physics and Astronomy
In this thesis I will outline various quantum phase transitions in 2D models of magnets that are amenable to simulation with quantum Monte Carlo techniques. The key player in this work is the theory of deconfined criticality, which generically allows for zero temperature quantum phase transitions between phases that break distinct global symmetries. I will describe models with different symmetries including SU(N), SO(N), and "easy-plane" SU(N) and I will demonstrate how the presence or absence of continuous transitions in these models fits together with the theory of deconfined criticality.
Thermal Conductivities Of Organic Semiconductors, Yulong Yao
Thermal Conductivities Of Organic Semiconductors, Yulong Yao
Theses and Dissertations--Physics and Astronomy
Organic semiconductors have gained a lot of interest due to their ease of processing, low-cost and inherent mechanical flexibility. Although most of the research has been on their electronic and optical properties, knowledge of the thermal properties is important in the design of electronic devices as well. Our group has used ac-calorimetric techniques to measure both in-plane and transverse thermal conductivities of a variety of organic semiconductors including small-molecule crystals and polymer blends. For layered crystals composed of molecules with planar backbones and silylethynyl (or germylethynyl) sidegroups projecting between the layers, very high interplanar thermal conductivities have been observed, presumably …
Tuning The Effective Electron Correlation In Iridate Systems Featuring Strong Spin-Orbit Interaction, John H. Gruenewald
Tuning The Effective Electron Correlation In Iridate Systems Featuring Strong Spin-Orbit Interaction, John H. Gruenewald
Theses and Dissertations--Physics and Astronomy
The 5d transition metal oxides have drawn substantial interest for predictions of being suitable candidates for hosting exotic electronic and magnetic states, including unconventional superconductors, magnetic skyrmions, topological insulators, and Weyl semimetals. In addition to the electron-electron correlation notable in high-temperature 3d transition metal superconductors, the 5d oxides contain a large spin-orbit interaction term in their ground state, which is largely responsible for the intricate phase diagram of these materials. Iridates, or compounds containing 5d iridium bonded with oxygen, are of particular interest for their spin-orbit split Jeff = 1/2 state, which is partially filled without the presence …