From magnetism to one-dimensional spin liquid in the anisotropic triangular lattice

TL;DR

This paper explores the transition from magnetic order to a one-dimensional spin liquid in an anisotropic triangular lattice, revealing a broad non-magnetic phase with strong one-dimensional features relevant for certain materials.

Contribution

It introduces a novel resonating valence bond wave function with singlet and triplet pairing, accurately capturing the destruction of magnetic order and emergence of spin liquids.

Findings

Magnetic order is rapidly suppressed away from the pure triangular lattice.

A wide phase diagram region hosts a non-magnetic spin liquid with one-dimensional characteristics.

Triplet pairing is relevant for understanding the properties of $$CuCl$_4$ and related materials.

Abstract

We investigate the anisotropic triangular lattice that interpolates from decoupled one-dimensional chains to the isotropic triangular lattice and has been suggested to be relevant for various quasi-two-dimensional materials, such as Cs$_2$CuCl$_4$ or $\kappa$-(ET)$_2$Cu$_2$(CN)$_3$, an organic material that shows intriguing magnetic properties. We obtain an excellent accuracy by means of a novel representation for the resonating valence bond wave function with both singlet and triplet pairing. This approach allows us to establish that the magnetic order is rapidly destroyed away from the pure triangular lattice and incommensurate spin correlations are short range. A non-magnetic spin liquid naturally emerges in a wide range of the phase diagram, with strong one-dimensional character. The relevance of the triplet pairing for $\kappa$-(ET)$_2$Cu$_2$(CN)$_3$ is also discussed.