Spin Liquid Phases for Spin-1 systems on the Triangular lattice

TL;DR

This paper proposes two novel gapless spin liquid phases for spin-1 systems on a triangular lattice, consistent with experimental observations in Ba3NiSb2O9, and explores their gauge symmetries and related ordered states.

Contribution

It introduces two new spin liquid phases with specific gauge structures and links them to experimental results and potential ordered states.

Findings

Both phases exhibit quadratic band touching with constant low-temperature susceptibility.

The phases have distinct gauge symmetry breakings: U(1)xZ_2 for type A, Z_4 for type B.

Type A phase is a parent state for various ordered magnetic and quadrupolar states.

Abstract

Motivated by recent experiments on material Ba3NiSb2O9, we propose two novel spin liquid phases (A and B) for spin-1 systems on a triangular lattice. At the mean field level, both spin liquid phases have gapless fermionic spinon excitations with quadratic band touching, thus in both phases the spin susceptibility and C_v/T saturate to a constant at zero temperature, which are consistent with the experimental results on Ba3NiSb2O9. On the lattice scale, these spin liquid phases have Sp(4) ~ SO(5) gauge fluctuation; while in the long wavelength limit this Sp(4) gauge symmetry is broken down to U(1)xZ_2 in type A spin liquid phase, and broken down to Z_4 in type B phase. We also demonstrate that the $A$ phase is the parent state of the ferro-quadrupole state, nematic state, and the noncollinear spin density wave state.