Exotic criticality in the dimerized spin-1 $XXZ$ chain with single-ion anisotropy

TL;DR

This paper investigates the phase transitions in a dimerized spin-1 XXZ chain with single-ion anisotropy, revealing complex critical behavior including Gaussian and Ising transitions and their experimental relevance.

Contribution

It provides a detailed analysis of the phase diagram and critical phenomena in the dimerized spin-1 XXZ chain with single-ion anisotropy, highlighting new universality classes.

Findings

Identification of phase boundaries between large-D, antiferromagnetic, and Haldane phases.

Discovery of Gaussian and Ising quantum phase transitions separating these phases.

Observation of a critical point in the dilute Ising universality class.

Abstract

We consider the dimerized spin-1 $XXZ$ chain with single-ion anisotropy $D$. In absence of an explicit dimerization there are three phases: a large-$D$, an antiferromagnetically ordered and a Haldane phase. This phase structure persists up to a critical dimerization, above which the Haldane phase disappears. We show that for weak dimerization the phases are separated by Gaussian and Ising quantum phase transitions. One of the Ising transitions terminates in a critical point in the universality class of the dilute Ising model. We comment on the relevance of our results to experiments on quasi-one-dimensional anisotropic spin-1 quantum magnets.