Magnetic quantum phases of spin-orbit-coupled anisotropic dipolar bosons in square lattices

TL;DR

This paper explores the rich quantum phase diagram of spin-orbit-coupled dipolar bosons in square lattices, revealing novel finite-momentum phases and phase transitions influenced by dipole tilt and interactions.

Contribution

It introduces a comprehensive analysis of quantum phases in anisotropic dipolar bosons with spin-orbit coupling, highlighting new finite-momentum crystal phases and phase transition mechanisms.

Findings

Finite-momentum superfluid and supersolid states induced by spin-orbit coupling.

Quantum phase transition at a magic tilt angle where off-site interaction vanishes.

Emergence of density-correlated phases, lattice-induced supersolid, and ferromagnetic phases.

Abstract

We examine the two-dimensional spin-orbit-coupled bosons in the presence of an anisotropic dipolar interaction in square lattices. The spin-orbit coupling leads to finite-momentum superfluid and supersolid states, while the nearest-neighbour interaction induces crystalline characteristics in the quantum phases of soft-core bosons. We employ site-decoupled Gutzwiller ansatz and mean-field decoupling theory to obtain the phase diagrams and investigate the effects of the tilt of magnetic dipoles with respect to the polarization axis. Our study reveals the intriguing quantum phase transition of checkerboard finite-momentum phase-twisted and phase-stripe states into their stripe counterparts at a magic tilt angle, at which the off-site interaction along one of the directions becomes zero. At smaller tilt angles, the checkerboard charge-density-wave phase intervened by two compressible finite-momentum phases, and at strong spin-orbit coupling strengths, the phase-twisted supersolid and superfluid phases emerge. At larger tilt angles, a transition between the striped order of phase-twisted states and phase-stripe states occurs. The inclusion of off-site inter-component correlation leads to density-correlated phases, lattice-induced supersolid, and ferromagnetic quantum phases. Our study highlights novel finite-momentum crystal phases of spin-orbit-coupled dipolar bosons and provides a parameter space to observe them in quantum gas experiments.