Quantum phase transition in the Plaquette lattice with anisotropic spin exchange

TL;DR

This paper investigates how anisotropic spin exchanges, specifically Dzyaloshinskii-Moriya and four-spin interactions, influence quantum phase transitions in the Plaquette lattice, revealing their roles in stabilizing different magnetic orders.

Contribution

It provides a detailed analysis of the effects of anisotropic exchanges on quantum phase transitions using exact diagonalization, highlighting their contrasting influences on magnetic order stabilization.

Findings

Dzyaloshinskii-Moriya exchange stabilizes Neel-like order.

Four-spin exchange can stabilize singlet or Neel-like order depending on strength.

The study advances understanding of anisotropic interactions in quantum magnetic systems.

Abstract

I study the influence of anisotropic spin exchange on a quantum phase transition in the Plaquette lattice driven by the purely quantum effect of singlet formation. I study the influence of i) a Dzyaloshinskii-Moriya exchange and ii) four spin exchange on the transition point by evaluating spin--spin correlations and the spin gap with exact diagonalization. The results point to a stabilization of the Neel-like long range order when the Dzyaloshinskii-Moriya exchange is added, whereas the four-spin exchange might stabilize the singlet order as well as the Neel-like order depending on its strength.