Physics Commons^™

Band Structure Topology And Spin Transport In Magnon Systems, Bo Li

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

As the spin excitation quanta in magnetic materials, the magnon is at the heart of the spintronics research because it plays a key role in magnetic dynamics, energy and spin transport, and even determining the ground state of magnetic systems. In this thesis, we will study the band-structure topology and transport properties of magnons in both collinear and noncollinear magnets. Inspired by the great success of topological insulators, exploring magnon topology can unveil the topological nature of bosonic particles and widen the zoo of topological materials. We propose a three-dimensional magnon topological insulator model protected by sublattice chiral symmetries, which …

Ab-Initio And Model Studies Of Spin Fluctuation Effects In Transport And Thermodynamics Of Magnetic Metals, James K. Glasbrenner

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

Magnetic materials are vital to many devices and the manipulation of spins is central to the operation of novel devices such as spin transistors. It is important to understand the effect of spin fluctuations on such systems. In this dissertation, first-principles calculations and models further the understanding of spin fluctuation effects in the transport and thermodynamics of magnetic metals.

A simple classical spin-fluctuation Hamiltonian with a single itinerancy parameter is studied using the mean-field approximation, Monte Carlo simulations, and a generalized Onsager cavity field method. The results of these different methods are in agreement. It is found that the thermodynamics …