Paired chiral spin liquid with a Fermi surface in S=1 model on the triangular lattice

TL;DR

This paper explores potential quantum spin liquid states in a spin-1 model on a triangular lattice, identifying a stable paired chiral spin liquid with a Fermi surface under specific conditions, relevant to recent experiments.

Contribution

It introduces a novel paired chiral quantum spin liquid with a Fermi surface in an SU(3)-invariant model, supported by variational Monte Carlo calculations.

Findings

No spin liquid phase in the antiferromagnetic Heisenberg model with biquadratic and anisotropy.

Stable paired chiral spin liquid with a Fermi surface found in SU(3) model with ring-exchange.

Proposes experimental tests for the exotic spin liquid state.

Abstract

Motivated by recent experiments on Ba3NiSb2O9, we investigate possible quantum spin liquid ground states for spin S=1 Heisenberg models on the triangular lattice. We use Variational Monte Carlo techniques to calculate the energies of microscopic spin liquid wave functions where spin is represented by three flavors of fermionic spinon operators. These energies are compared with the energies of various competing three-sublattice ordered states. Our approach shows that the antiferromagnetic Heisenberg model with biquadratic term and single-ion anisotropy does not have a low-temperature spin liquid phase. However, for an SU(3)-invariant model with sufficiently strong ring-exchange terms, we find a paired chiral quantum spin liquid with a Fermi surface of deconfined spinons that is stable against all types of ordering patterns we considered. We discuss the physics of this exotic spin liquid state in relation with the recent experiment and suggest new ways to test this scenario.