Triplet resonating valence bond theory and transition metal chalcogenides

TL;DR

This paper introduces a triplet resonating valence bond (tRVB) theory for quantum spin liquids in 2D magnets, explores its transferability from singlet RVB, and discusses implications for transition metal chalcogenides like 1T-TaS2.

Contribution

It develops a novel triplet RVB framework, extends mean field theories to 2D lattices, and links the theory to real materials such as transition metal chalcogenides.

Findings

tRVB states can be stabilized in 2D quantum magnets.

Charge doping can induce p+ip-wave superconductivity.

The theory may explain the spin-liquid behavior in 1T-TaS2.

Abstract

We develop a quantum spin liquid theory for quantum magnets with easy-plane ferromagnetic exchange. These strongly entangled quantum states are obtained by dimer coverings of 2D lattices with triplet $S = 1, m_z = 0$ bonds, forming a triplet resonating valence bond (tRVB) state. We discuss the conditions and the procedure to transfer well-known results from conventional singlet resonating valence bond theory to tRVB. Additionally, we present mean field theories of Abrikosov fermions on 2D triangular and square lattices, which can be controlled in an appropriate large $N$ limit. We also incorporate the effect of charge doping which stabilizes $p+ip$-wave superconductivity. Beyond the pure theoretical interest, our study may help to resolve contradictory statements on certain transition metal chalcogenides, including 1T-TaS$_2$, as a potential tRVB spin-liquid.