Agenda

Résumé : Thermal Hall conductivity has recently emerged as an experimentally accessible property of insulating materials. Theoretical understanding thereof has remained a challenge, in particular since the breaking of time-reversal symmetry by neutral particles is nontrivial and can emerge from multiple mechanisms (intrinsic semiclassical dynamics, skew-scattering, disorder side-jump effects, etc). In this seminar, I will show that many of these effects can be studied together within a kinetic (Boltzmann-like) formalism. First, I will briefly discuss inelastic skew-scattering of energy-carrying bosons by other collective excitations, with applications to phonon-magnon interactions in antiferromagnets. Second, I will present how anomalous contributions to the semiclassical dynamics of carriers can be incorporated in a rigorous way, yielding the intrinsic thermal Hall effect of chiral bosons (e.g. magnons in frustrated magnets). Finally, I will discuss side-jump phenomena, a mixed effect of disorder scattering and semiclassical dynamics that may explain some puzzling experimental facts.