# Finite-temperature phase transition to a Kitaev spin liquid phase on a hyperoctagon lattice: A large-scale quantum Monte Carlo study

## TL;DR

This study uses large-scale quantum Monte Carlo simulations to explore a finite-temperature phase transition to a Kitaev quantum spin liquid on a hyperoctagon lattice, revealing a liquid-gas transition similar to that on a hyperhoneycomb lattice.

## Contribution

It demonstrates the occurrence of a liquid-gas phase transition in the Kitaev model on the hyperoctagon lattice using advanced Monte Carlo methods, expanding understanding of 3D quantum spin liquids.

## Key findings

- Critical temperature is lower than in hyperhoneycomb lattice.
- A liquid-gas transition occurs in the hyperoctagon lattice.
- The transition is analyzed via an effective model in the anisotropic limit.

## Abstract

The quantum spin liquid is an enigmatic quantum state in insulating magnets, in which conventional long-range order is suppressed by strong quantum fluctuations. Recently, an unconventional phase transition was reported between the low-temperature quantum spin liquid and the high-temperature paramagnet in the Kitaev model on a three-dimensional hyperhoneycomb lattice. Here, we show that a similar "liquid-gas" transition takes place in another three-dimensional lattice, the hyperoctagon lattice. We investigate the critical phenomena by adopting the Green-function based Monte Carlo technique with the kernel polynomial method, which enables systematic analysis of up to 2048 sites. The critical temperature is lower than that in the hyperhoneycomb case, reflecting the smaller flux gap. We also discuss the transition on the basis of an effective model in the anisotropic limit.