First-Principles Multiscale Modelling of Quantum Materials
| Date/Time: | Thursday, 11 Apr 2019 from 4:10 pm to 5:00 pm |
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| Location: | Phys 0003 |
| Phone: | 515-294-5441 |
| Channel: | College of Liberal Arts and Sciences |
| Actions: | Download iCal/vCal | Email Reminder |
ABSTRACT: Quantum materials represent a broad class of systems whose experimental response relies directly on entanglement between their underlying degrees of freedom. Modelling of such materials presents a variety of challenges related to (i) a disparate variety of complex behaviours that manifest at different time and energy scales, and (ii) the emergence of new effective degrees of freedom as a material is probed at lower and lower energies. In this vein, first-principles approaches 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 briefly discuss the insights that these methods have yielded for a class of frustrated magnetic insulators collectively known as "Kitaev materials". As a consequence of strong spin-orbit coupling, these materials feature bond-dependent spin interactions reminiscent of Kitaev's honeycomb model - which features a spin-liquid ground state with Ising anyon topological order. While such a spin-liquid has not yet been realised in a real material, the magnetically ordered phases of the known materials (e.g. alpha-RuCl3) display unconventional dynamical responses, as probed by e.g. neutron scattering. We show how consideration of the full range of interactions revealed by first principles calculations has provided a consistent explanation of these experimental findings.
BIO: Steve is currently a Junior Project Leader at the Institute for Theoretical Physics in Frankfurt Germany. He previously completed his PhD at the University of Waterloo, Canada on the subject of strongly correlated organic materials. His research career has spanned a variety of topics in chemistry and physics, which has included a combination of synthetic, experimental, and theoretical efforts.