Phase Diagram of the Kitaev-type Model on a Decorated Honeycomb Lattice in the Isolated Dimer Limit

TL;DR

This paper studies a Kitaev-type model on a decorated honeycomb lattice, revealing a chiral spin liquid ground state and analyzing its finite-temperature phase transitions using mean-field and Monte Carlo methods.

Contribution

It provides an exact characterization of the chiral spin liquid ground state and explores the finite-temperature phase diagram with numerical simulations.

Findings

Ground state is a chiral spin liquid with broken time reversal symmetry

Phase transition is second order and in the 2D Ising universality class

Tricritical point appears in the mean-field phase diagram

Abstract

An effective model in the isolated dimer limit of the Kitaev-type model on a decorated honeycomb lattice is investigated at finite temperature. The ground state of this model is exactly shown to be a chiral spin liquid with spontaneous breaking of time reversal symmetry. We elaborate the finite-temperature phase diagram by using the mean-field approximation and Monte Carlo simulation. We find that the phase transition between the high-temperature paramagnetic phase and the low-temperature chiral spin liquid phase is always of second order in the Monte Carlo results, although a tricritical point appears in the mean-field phase diagram. The finite-size scaling analysis of the Monte Carlo data indicates that the phase transition belongs to the two-dimensional Ising universality class.