Regensburg 2022 – wissenschaftliches Programm
KFM 30.9: Vortrag
Freitag, 9. September 2022, 11:30–11:45, H37
The nature of visons in the perturbed ferromagnetic and antiferromagnetic Kitaev honeycomb models — Chuan Chen1 and •Inti Sodemann Villadiego2,3 — 1Institute for Advanced Study, Tsinghua University, 100084 Beijing, China — 2Institut für Theoretische Physik, Universität Leipzig, 04103 Leipzig, Germany — 3Max-Planck Institute for the Physics of Complex Systems, 01187 Dresden, Germany
The Kitaev honeycomb model hosts a fascinating fractionalized state of matter that features emergent Majorana fermions and a vison particle that carries the flux of an emergent gauge field. In the exactly solvable limit, these visons are static, but perturbations can induce their motion.
We show that the nature of the vison motion is sharply distinct in the ferromagnetic vs the anti-ferromagnetic Kitaev models. Namely, in the ferromagnetic model the vison has a trivial non-projective translational symmetry, whereas in the anti-ferromagnetic Kitaev model it has a projective translational symmetry with pi-flux per unit cell. The visons of the FM case have zero Berry curvature, and no associated intrinsic contribution to the Thermal Hall effect. In contrast, in the AFM case and under a Zeeman perturbing field, there are two gapped vison bands with opposite Chern numbers and an associated intrinsic vison contribution to the Thermal Hall effect. We will comment on other results in the literature that are in disagreement with ours (arXiv:2109.00250, 2021) and discuss the potential connections of our findings to the physics of the spin liquid candidate alpha-RuCl_3.