Spin Liquid in the Multiple-Spin Exchange model on the Triangular lattice: 3He on graphite

TL;DR

This paper uses exact diagonalization to explore the phase diagram of the Multi-Spin Exchange model on a triangular lattice, revealing a transition from ferromagnetic to spin liquid phases and analyzing thermodynamic properties relevant to 3He on graphite.

Contribution

It provides the first detailed phase diagram of the MSE model on the triangular lattice, identifying a quantum phase transition and thermodynamic signatures relevant to 3He films.

Findings

Identified a phase transition between ferromagnetic and spin liquid phases.

Observed magnetization plateaus at 0 and 1/2 saturation.

Found a double-peak structure in heat capacity for 3He parameters.

Abstract

Using exact diagonalizations, we investigate the T=0 phase diagram of the Multi-Spin Exchange (MSE) model on the triangular lattice: we find a transition separating a ferromagnetic phase from a non-magnetic gapped Spin Liquid phase. Systems far enough from the ferromagnetic transition have a metamagnetic behavior with magnetization plateaus at m/m_sat=0 and 1/2. The MSE has been proposed to describe solid 3He films adsorbed onto graphite, thus we compute the MSE heat capacity for parameters in the low density range of the 2nd layer and find a double-peak structure.