Quantum dimer model for the spin-1/2 kagome Z2 spin liquid

TL;DR

This paper refines the quantum dimer model for the spin-1/2 kagome antiferromagnet, showing that environment-dependent modifications support a Z2 spin liquid state over a valence-bond crystal, aligning with recent DMRG findings.

Contribution

It introduces environment-sensitive adjustments to the quantum dimer model, providing a more accurate description of the kagome spin liquid state compared to previous models.

Findings

Parameters favor a Z2 spin liquid state

Environment effects significantly alter loop process amplitudes

Results align with recent DMRG studies

Abstract

We revisit the description of the low-energy singlet sector of the spin-1/2 Heisenberg antiferromagnet on kagome in terms of an effective quantum dimer model. With the help of exact diagonalizations of appropriate finite-size clusters, we show that the embedding of a given process in its kagome environment leads to dramatic modifications of the amplitudes of the elementary loop processes, an effect not accessible to the standard approach based on the truncation of the Hamiltonian to the nearest-neighbour valence-bond basis. The resulting parameters are consistent with a Z$_2$ spin liquid rather than with a valence-bond crystal, in agreement with the last density matrix renormalization group results.