Supersolidity in a Bose-Holstein model

TL;DR

This paper derives an effective Hamiltonian for hard-core bosons coupled to phonons, demonstrating how supersolidity emerges due to next-nearest-neighbor hopping and repulsion, providing a microscopic mechanism for coexistence of orders.

Contribution

It introduces a microscopic model explaining supersolidity in a Bose-Holstein system through specific hopping and interaction terms.

Findings

Superfluid-supersolid transition at intermediate couplings.

Phase separation at strong couplings.

Supersolidity driven by next-nearest-neighbor hopping and repulsion.

Abstract

We derive an effective d-dimensional Hamiltonian for a system of hard-core-bosons coupled to optical phonons in a lattice. At non-half-fillings, a superfluid-supersolid transition occurs at intermediate boson-phonon couplings, while at strong-couplings the system phase separates. We demonstrate explicitly that the presence of next-nearest-neighbor hopping and nearest-neighbor repulsion leads to supersolidity. Thus we present a microscopic mechanism for the homogeneous coexistence of charge-density-wave and superfluid orders.