Thermal Quench Dynamics of Visons in Gapless Kitaev Spin Liquid

TL;DR

This paper investigates the thermal quench dynamics of visons in the gapless Kitaev spin liquid, revealing complex behaviors like diffusion, annihilation, and freezing linked to vison interactions and emergent symmetries.

Contribution

It provides a detailed kinetic Monte Carlo simulation study of vison dynamics, uncovering new temperature-dependent behaviors and the role of metastable vison crystal formation.

Findings

Vison diffusion and pair annihilation are influenced by temperature.

Freezing occurs due to metastable vison crystal formation.

Broken symmetry and super-cluster coarsening are observed.

Abstract

The relaxation dynamics of the Kitaev honeycomb model under a thermal quench is dominated by the quasi-stochastic diffusion and pair annihilation of visions, which are gapped flux excitations of an emergent $\mathbb{Z}_2$ gauge field of the Kitaev spin liquid. Both the diffusion energy barrier as well as the effective interactions between visons are mediated by the Majorana fermions which are fractionalized quasiparticles of the spin liquid. Through extensive kinetic Monte Carlo simulations, we show that the interplay between the thermal diffusion and nonlocal multi-vision interactions leads to a variety of temperature-dependent dynamical behaviors ranging from diffusion-limited and terminal-velocity-limited annihilation to dynamical arresting and freezing. Notably, we show that the freezing phenomenon is intimately related to the formation of metastable $\sqrt{3}\times\sqrt{3}$ vison crystals and a hidden coarsening of super-clusters associated with a broken $\mathbb{Z}_3$ symmetry.