Frustration-induced supersolids in the absence of inter-site interactions

TL;DR

This paper proposes a new mechanism for realizing supersolids in optical lattices without inter-site interactions, using frustration effects in the sawtooth lattice to induce supersolidity at unit filling.

Contribution

It introduces a novel approach to create supersolids relying solely on lattice geometry and frustration, eliminating the need for long-range interactions.

Findings

Supersolids can form in sawtooth lattices due to frustration effects.

The supersolid phase exists over a wide parameter range above half filling.

This mechanism enables realization of supersolids in ultracold gases without long-range interactions.

Abstract

We discuss a mechanism for the realization of supersolids in lattices in the absence of intersite interactions that surprisingly works as well at unit filling. This mechanism, that we study for the case of the sawtooth lattice, is based on the existence of frustrated and unfrustrated plaquettes. For sufficiently large interactions and frustration the particles gather preferentially at unfrustrated plaquettes breaking spontaneously translational invariance, resulting in a supersolid. We show that for the sawtooth lattice the supersolid exists for a large region of parameters for densities above half filling. Our results open a feasible path for realizing supersolids in existing ultracold atomic gases in optical lattices without the need for long-range interactions.