Supersolid phase in spin dimer XXZ systems under magnetic field

TL;DR

This study uses quantum Monte Carlo simulations to explore the phase diagram of a 2D spin dimer XXZ system under magnetic fields, revealing a supersolid phase with unique symmetry-breaking properties.

Contribution

It demonstrates the existence of a supersolid phase in a spin dimer model with specific anisotropy, expanding understanding of quantum phases in such systems.

Findings

Identification of a supersolid phase with broken translational symmetry.

Presence of checkerboard solid and two superfluid phases.

Model realization through next nearest neighbor coupling among dimers.

Abstract

Using quantum Monte Carlo method, we study, under external magnetic fields, the ground state phase diagram of the two-dimensional spin $S$=1/2 dimer model with an anisotropic intra-plane antiferromagnetic coupling. With the anisotropy $4 \gtrsim \Delta \gtrsim 3$, a supersolid phase characterized by a non-uniform bose condensate density that breaks translational symmetry is found. The rich phase diagram also contains a checkerboard solid and two different types of superfluid phase formed by $S_z=+1$ and $S_z=0$ spin triplets, with finite staggered magnetization in z-axis and in-plane direction, respectively. As we show, the model can be realized as a consequence of including the next nearest neighbor coupling among dimers and our results suggest that spin dimer systems may be an ideal model system to study the supersolid phase.