Magnetic and nematic orderings in spin-1 antiferromagnets with single-ion anisotropy

TL;DR

This paper investigates the phase diagram of a spin-1 antiferromagnetic model with anisotropy and magnetic field, revealing a transition between XY-antiferromagnetic and ferronematic phases, akin to BEC of single bosons and pairs.

Contribution

It combines analytical and Quantum Monte Carlo methods to map the (D/J,B/J) phase diagram for square and cubic lattices, identifying a novel ferronematic phase transition.

Findings

Identified a transition between XY-antiferromagnetic and ferronematic phases.

Mapped the quantum phase diagram for different lattice types.

Proposed experimental avenues for observing the transition in real magnets.

Abstract

We study a spin-one Heisenberg model with exchange interaction, J, uniaxial single-ion exchange anisotropy, D, and Zeeman coupling to a magnetic field, B, parallel to the symmetry axis. We com- pute the (D/J,B/J) quantum phase diagram for square and simple cubic lattices by combining an- alytical and Quantum Monte Carlo approaches, and find a transition between XY-antiferromagnetic and ferronematic phases that spontaneously break the U(1) symmetry of the model. In the language of bosonic gases, this is a transition between a Bose-Einstein condensate (BEC) of single bosons and a BEC of pairs. Our work opens up new avenues for measuring this transition in real magnets.