Spin Nematic Phase in S=1 Triangular Antiferromagnets

TL;DR

This paper investigates the spin nematic phase in S=1 triangular antiferromagnets, revealing unique excitations and properties that explain experimental observations in NiGa2S4.

Contribution

It introduces a detailed analysis of the antiferro nematic order with a three-sublattice structure using bosonization, highlighting novel excitations and magnetic behaviors.

Findings

Identification of a gapless bosonic excitation with linear dispersion

Finite spin susceptibility at zero temperature

Specific heat behavior $C(T) \\sim T^2$ at low temperatures

Abstract

Spin nematic order is investigated for a S=1 spin model on triangular lattice with bilinear-biquadratic interactions. We particularly studied an antiferro nematic order phase with three-sublattice structure, and magnetic properties are calculated at zero temperature by means of bosonization. Two types of bosonic excitations are found. One is a gapless excitation with linear energy dispersion around $k \sim 0$, and this leads to a finite spin susceptibility at T=0 and would have a specific heat $C(T) \sim T^2$ at low temperatures. These behaviors can explain many of characteristic features of recently discovered spin liquid state in the triangular magnet, NiGa2S4.