Spin nematic ground state of the triangular lattice S=1 biquadratic model

TL;DR

This paper investigates a spin-1 triangular lattice model with biquadratic interactions, revealing a spin nematic ground state through efficient quantum Monte Carlo simulations, and provides detailed thermodynamic and field theory parameters.

Contribution

It introduces a new quantum Monte Carlo approach for the spin-1 biquadratic model and characterizes its spin nematic ground state and low-energy properties.

Findings

Ground state exhibits spin nematic order.

Efficient QMC sampling enabled large lattice analysis.

Provides parameters for low-energy effective field theory.

Abstract

Motivated by the spate of recent experimental and theoretical interest in Mott insulating S=1 triangular lattice magnets, we consider a model S=1 Hamiltonian on a triangular lattice interacting with rotationally symmetric biquadratic interactions. We show that the partition function of this model can be expressed in terms of configurations of three colors of tightly-packed, closed loops with {\em non-negative} weights, which allows for efficient quantum Monte Carlo sampling on large lattices. We find the ground state has spin nematic order, i.e. it spontaneously breaks spin rotation symmetry but preserves time reversal symmetry. We present accurate results for the parameters of the low energy field theory, as well as finite-temperature thermodynamic functions.