Quantum Spin Liquid in a Breathing Kagome Lattice

TL;DR

This paper investigates the stabilization of a gapped $Z_2$ quantum spin liquid in a breathing kagome lattice, using symmetry analysis and variational Monte Carlo, motivated by recent experimental findings.

Contribution

It identifies a gapped $Z_2$ spin liquid as the ground state in a breathing kagome lattice, linking symmetry analysis with numerical methods and experimental relevance.

Findings

Gapped $Z_2$ spin liquid is the ground state with breathing anisotropy.

Breathing anisotropy stabilizes the spin liquid phase.

Results align with recent experimental observations.

Abstract

Motivated by recent experiments on the vanadium oxyfluoride material DQVOF, we examine possible spin liquid phases on a breathing kagome lattice of S=1/2 spins. By performing a projective symmetry group analysis, we determine the possible phases for both fermionic and bosonic $\mathbb{Z}_2$ spin liquids on this lattice, and establish the correspondence between the two. The nature of the ground state of the Heisenberg model on the isotropic kagome lattice is a hotly debated topic, with both $\mathbb{Z}_2$ and U(1) spin liquids argued to be plausible ground states. Using variational Monte Carlo techniques, we show that a gapped $\mathbb{Z}_2$ spin liquid emerges as the clear ground state in the presence of this breathing anisotropy. Our results suggest that the breathing anisotropy helps to stabilize this spin liquid ground state, which may aid us in understanding the results of experiments and help to direct future numerical studies on these systems.