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TT: Fachverband Tiefe Temperaturen
TT 30: Matter At Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ... 1
TT 30.9: Talk
Wednesday, March 28, 2012, 17:45–18:00, H 3005
Supersolid phase transitions for hard-core bosons on a triangular lattice — •Xue-Feng Zhang1,2, Raoul Dillenschneider1, Yue Yu2, and Sebastian Eggert1 — 1Department of Physics, University of Kaiserslautern, D-67663 Kaiserslautern, Germany — 2Institute of Theoretical Physics, Chinese Academy of Sciences, P.O. Box 2735, Beijing 100190, China
Hard-core bosons on a triangular lattice with nearest-neighbor repulsion are a prototypical example of a system with supersolid behavior on a lattice. We show that in this model the physical origin of the supersolid phase can be understood quantitatively and analytically by constructing quasiparticle excitations of defects that are moving on an ordered background. The location of the solid to supersolid phase transition line is predicted from the effective model for both positive and negative (frustrated) hopping parameters. For positive hopping parameters the calculations agree very accurately with numerical quantum Monte Carlo simulations. The numerical results indicate that the supersolid to superfluid transition is first order.