Mott glass in site-diluted S=1 antiferromagnets with single-ion anisotropy

TL;DR

This study uses quantum Monte Carlo simulations to explore how site dilution and single-ion anisotropy induce a Mott glass phase in S=1 antiferromagnets, revealing a quantum-disordered state before percolation.

Contribution

It demonstrates the emergence of a Mott glass phase driven by quantum fluctuations and site dilution in S=1 antiferromagnets, extending understanding of disordered quantum magnetic states.

Findings

Quantum fluctuations destroy Néel order before the percolation threshold at high anisotropy.

A gapless Mott glass phase appears on the percolated lattice with vanishing susceptibility.

The critical anisotropy for destabilizing order is identified as D^* = 2.3(2) J.

Abstract

The interplay between site dilution and quantum fluctuations in S=1 Heisenberg antiferromagnets on the square lattice is investigated using quantum Monte Carlo simulations. Quantum fluctuations are tuned by a single-ion anisotropy D. In the clean limit, a sufficiently large D>D_c = 5.65(2) J forces each spin into its m_S=0 state, and thus destabilizes antiferromagnetic order. In the presence of site dilution, quantum fluctuations are found to destroy N\'eel order before the percolation threshold of the lattice is reached, if D exceeds a critical value D^* = 2.3(2) J. This mechanism opens up an extended quantum-disordered Mott glass phase on the percolated lattice, characterized by a gapless spectrum and vanishing uniform susceptibility.