title: Supersolids versus phase separation in two-dimensional lattice bosons.
abstract: We study the nature of the ground state of the two-dimensional extended boson Hubbard model on a square lattice by quantum Monte Carlo methods. We demonstrate that strong but finite on-site interaction U along with a comparable nearest-neighbor repulsion V result in a thermodynamically stable supersolid ground state for densities larger than 1/2, in contrast to fillings less than 1/2 or for very large U, where the checkerboard supersolid is unstable towards phase separation. We discuss the relevance of our results to realizations of supersolids using cold bosonic atoms in optical lattices.
authors.affiliation: Department of Physics, University of California, Riverside, California 92521, USA.
authors.forename: Pinaki
authors.initials: P
authors.lastname: Sengupta
authors.forename: Leonid P
authors.initials: LP
authors.lastname: Pryadko
authors.forename: Fabien
authors.initials: F
authors.lastname: Alet
authors.forename: Matthias
authors.initials: M
authors.lastname: Troyer
authors.forename: Guido
authors.initials: G
authors.lastname: Schmid