Ground-state properties of a supersolid in RPA
Max-Planck-Institute for the Physics of Complex Systems, 01187 Dresden, Germany
2 Nonlinear Physics Centre, Australian National University, Canberra, ACT, 0200, Australia
Corresponding author: a email@example.com
Published online: 3 March 2009
We investigate the newly discovered supersolid phase by solving in random-phase approximation the anisotropic Heisenberg model of the hard-core boson 4He lattice at zero temperature. We include nearest and next-nearest neighbor interactions and calculate exactly all pair correlation functions in a cumulant decoupling scheme. We demonstrate the importance of vacancies and interstitials in the formation of the supersolid phase. The supersolid phase is characterised by strong quantum fluctuations which are taken into account rigorously. Furthermore we confirm that the superfluid to supersolid transition is triggered by a collapsing roton minimum however is stable against spontaneously induced superflow, i.e. vortex creation.
PACS: 05.30.Jp – Boson systems / 67.80.-s – Quantum solids / 67.80.bd – Superfluidity in solid 4He, supersolid 4He / 75.10.Jm – Quantized spin models
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009