Dissertation Defense: Ryan Nesselrodt

Candidate: Ryan Nesselrodt

Major: Physics

Advisor: James Freericks, Ph.D.

Title: An Exploration of Correlated Quantum Materials In and Out of Equilibrium

Correlated materials are those in which the simplest description of a solid, that of a sea of free electrons, unencumbered by each other, their nuclei, fear of god, or anything at all, fails. To properly describe the behavior of these materials one must consider some type of interaction between the electrons themselves, between electron and nuclei, between electrons in different orbitals, or some other interaction. These complex materials display interesting properties, like checkerboard or striped charge and spin orderings, magnetic phases, and superconductivity. I seek to account for features of these materials in extreme situations by using simple models which include an electron-electron interaction, an electron-lattice interaction or both.

In this report I present results from studies of the Falicov-Kimball Model, the non-equilibrium Holstein-Hubbard model, the generalized Hatsuagi-Kohmoto model and the static Holstein plus core-hole model. I begin with the necessary background to contextualize these results, and conclude with some comments on the implications of this work and possible future directions worth consideration.