Spin liquid phases of alkaline-earth-metal atoms at finite temperature

TL;DR

This paper investigates finite-temperature spin liquid phases of spin-5/2 alkaline earth atoms on a honeycomb lattice, identifying phase transitions and the stability of chiral spin liquids using a variational path-integral approach.

Contribution

It introduces a finite-temperature analysis of spin liquid phases with a Gutzwiller projection and saddle-point approximation, highlighting the existence of a chiral spin liquid phase.

Findings

Identification of a critical temperature for phase melting

Existence of a stable chiral spin liquid phase at finite temperature

Calculation of the spin structure factor as an experimental signature

Abstract

We study spin liquid phases of spin-5/2 alkaline earth atoms on a honeycomb lattice at finite temperatures. Our analysis is based on a Gutzwiller projection variational approach recast to a path-integral formalism. In the framework of a saddle-point approximation we determine spin liquid phases with lowest free energy and study their temperature dependence. We identify a critical temperature, where all the spin liquid phases melt and the system goes to the paramagnetic phase. We also study the stability of the saddle-point solutions and show that a time-reversal symmetry breaking state, a so called chiral spin liquid phase is realized even at finite temperatures. We also determine the spin structure factor, which, in principle, is an experimentally measurable quantity and is the basic tool to map the spectrum of elementary excitations of the system.