Chemistry Seminar Series – Steve Winter, Wake Forest University
Host: A. Wei Tsen
Quantum materials represent a broad class of systems whose experimental response relies directly on entanglement between their underlying degrees of freedom. Modeling of such materials presents a variety of challenges related to a disparate variety of complex behaviours that manifest at different energy scales, and a typical sensitivity of responses to model parameters. In this field, first-principles approaches often provide a vital bridge between experiments and theoretical models. In this talk, I will introduce our numerical strategies for systematically building low-energy models with local charge, spin, and orbital degrees of freedom of arbitrary complexity. I will discuss the insights that these methods have yielded for frustrated magnetic insulators collectively known as "Kitaev materials", which have prompted a recent explosion of interest in quantum magnets where spin-orbit coupling induces strongly anisotropic and competing magnetic interactions. I will specifically address our recent attempts to understand the magnetic models of few-layer RuCl3 and high-spin d7 Co(II) compounds, which have recently been identified as possible alternative platforms for realising the celebrated Kitaev model.