Hard-Core Repulsion and Supersolid Cluster Crystals
We study the effect of a short-ranged hard-core repulsion on the stability and superfluid properties of the cluster crystal phase of two-dimensional (2D) soft-core bosons. Results of Quantum Monte Carlo simulations on a cogent test case suggest that the main physical properties of the phase remain unaltered if the range d of the inner repulsive core is sufficiently short, even if the strength of the repulsion is several orders of magnitude greater than the outer soft-core barrier. Only if d is an appreciable fraction of the size of the clusters ( Open image in new window 5 %) does a sufficiently strong hard-core repulsion cause the crystal to break down into a homogeneous superfluid; a moderate inner core repulsion enhances the superfluid response of the crystalline phase.
KeywordsSupersolid phase of matter Rydberg atoms Quantum Monte Carlo simulations
This work was supported by the Natural Science and Engineering Research Council of Canada. Computing support of Westgrid is gratefully acknowledged.