Supersolid hardcore bosons on the triangular lattice

Abstract

We determine the phase diagram of hardcore bosons on a triangular lattice with nearest neighbor repulsion, paying special attention to the stability of the supersolid phase. Similar to the same model on a square lattice we find that for densities $ρ<1/3$ or $ρ>2/3$ a supersolid phase is unstable and the transition between a commensurate solid and the superfluid is of first order. At intermediate fillings $1/3 < ρ< 2/3$ we find an extended supersolid phase even at half filling $ρ=1/2$.