Two distinct spin liquid states in a layered cubic lattice

TL;DR

This paper constructs and analyzes a family of resonating-valence-bond wave functions on a layered cubic lattice, revealing four phases including two distinct quantum spin liquids with different correlation decay behaviors, separated by quantum phase transitions.

Contribution

It introduces a tunable family of RVB wave functions on a layered cubic lattice and demonstrates the existence of two distinct spin liquid states with different properties.

Findings

Four phases stabilized over the anisotropy range

Identification of two different quantum spin liquids

Existence of a gapped spin liquid despite bipartite structure

Abstract

We construct a family of short-range resonating-valence-bond wave functions on a layered cubic lattice, allowing for a tunable anisotropy in the amplitudes assigned to nearest-neighbour valence bonds along one axis. Monte Carlo simulations reveal that four phases are stabilized over the full range of the anisotropy parameter. They are separated from one another by a sequence of continuous quantum phase transitions. An antiferromagnetic phase, centred on the perfect isotropy point, intervenes between two distinct quantum spin liquid states. One of them is continuously deformable to the two-dimensional U(1) spin liquid, which is known to exhibit critical bond correlations. The other has both spin and bond correlations that decay exponentially. The existence of this second phase is proof that, contrary to expectations, neither a bipartite lattice structure nor a conventional Marshall sign rule is an impediment to realizing a fully gapped quantum spin liquid.