Stripes, topological order, and deconfinement in a planar t-Jz model

TL;DR

This paper maps the phase diagram of a 2D bosonic t-Jz model, revealing a static stripe phase with topological order at low anisotropy, and transitions to phase segregation or superfluidity at higher anisotropy.

Contribution

It analytically and numerically characterizes the phase diagram of the bosonic t-Jz model, highlighting the emergence of topological order and stripe phases.

Findings

Static stripe phase with topological order at low gamma

Quantum phase transition to phase segregation or superfluidity at higher gamma

Equivalence of bosonic and fermionic t-Jz models in the small gamma limit

Abstract

We determine the quantum phase diagram of a two-dimensional bosonic t-Jz model as a function of the lattice anisotropy gamma, using a quantum Monte Carlo loop algorithm. We show analytically that the low-energy sectors of the bosonic and the fermionic t-Jz models become equivalent in the limit of small gamma. In this limit, the ground state represents a static stripe phase characterized by a non-zero value of a topological order parameter. This phase remains up to intermediate values of gamma, where there is a quantum phase transition to a phase-segregated state or a homogeneous superfluid with dynamic stripe fluctuations depending on the ratio Jz/t.