Supersolid Order from Disorder: Hard-Core Bosons on the Triangular Lattice

TL;DR

This paper investigates how hard-core bosons on a triangular lattice exhibit a stable supersolid phase due to an order-by-disorder mechanism, even at strong repulsion and half-filling.

Contribution

It demonstrates the emergence of a stable supersolid phase in a model with geometric frustration and strong interactions, highlighting an order-by-disorder mechanism.

Findings

Superfluidity persists at large repulsion levels.

Diagonal solid order emerges from frustration.

Supersolid phase is stable at half-filling.

Abstract

We study the interplay of Mott localization, geometric frustration, and superfluidity for hard-core bosons with nearest-neighbor repulsion on the triangular lattice. For this model at half-filling, we demonstrate that superfluidity survives for arbitrarily large repulsion, and that diagonal solid order emerges in the strongly correlated regime from an order-by-disorder mechanism. This is thus an unusual example of a stable supersolid phase of hard-core lattice bosons at a commensurate filling.