Intrinsic Thermal Hall Effect in Mott Insulators

Date

May 9, 2025

Time

10:30 AM - 11:30 AM

Speaker

Dr. Emily Zhang

Affiliation

Stanford University

Language

en

Main Topic

Materialien

Host

Grit Rötzer

Description

In light of recent experimental data indicating a substantial thermal Hall effect in square lattice antiferromagnetic Mott insulators, we investigate whether a simple Mott insulator can sustain a finite thermal Hall effect. We verify that the answer is "no" if one performs calculations within a spin-only low-energy effective spin model with non-interacting magnons. However, by performing determinant quantum Monte Carlo simulations, we show the single-band t-t'-U Hubbard model coupled to an orbital magnetic field does support a finite thermal Hall effect when t'/=0 and B/=0 in the Mott insulating phase. We argue that the (carrier agnostic) necessary conditions for observing a finite thermal Hall effect are time-reversal and particle-hole symmetry breaking. By considering magnon-magnon scattering using a semi-classical Boltzmann analysis, we illustrate a physical mechanism by which finite transverse thermal conductivity may arise, consistent with our symmetry argument and numerical results. Our results contradict the conventional wisdom that square and triangular lattices with SU(2) symmetry do not support a finite thermal Hall effect and call for a critical re-examination of thermal Hall effect data in insulating magnets, as the magnon contribution should not be excluded a priori. .

Links

• Seminars at the IFW

Last modified: Apr 26, 2025, 7:37:31 AM