Issue
EPL
Volume 87, Number 3, August 2009
Article Number 36002
Number of page(s) 5
Section Condensed Matter: Structural, Mechanical and Thermal Properties
DOI http://dx.doi.org/10.1209/0295-5075/87/36002
Published online 28 August 2009
EPL, 87 (2009) 36002
DOI: 10.1209/0295-5075/87/36002

Commensurate lock-in and incommensurate supersolid phases of hard-core bosons on anisotropic triangular lattices

Sergei V. Isakov1, Hong-Chi Chien2, Jian-Jheng Wu3, Yung-Chung Chen4, Chung-Hou Chung3, Krishnendu Sengupta5 and Yong Baek Kim1

1   Department of Physics, University of Toronto - Toronto, Ontario M5S 1A7, Canada
2   Department of Physics, National Tsing Hua University - Hsinchu, Taiwan 30013 ROC
3   Electrophysics Department, National Chiao Tung University - Hsinchu, Taiwan 300 ROC
4   Department of Physics, Tunghai University - Taichung, Taiwan 407 ROC
5   Theoretical Physics Division, Indian Association for the Cultivation of Sciences - Kolkata-700032, India


received 1 May 2009; accepted in final form 24 July 2009; published August 2009
published online 28 August 2009

Abstract
We investigate the interplay between commensurate lock-in and incommensurate supersolid phases of the hard-core bosons at half-filling with anisotropic nearest-neighbor hopping and repulsive interactions on triangular lattice. We use numerical quantum and variational Monte Carlo as well as analytical Schwinger boson mean-field analysis to establish the ground states and phase diagram. It is shown that, for finite-size systems, there exist a series of jumps between different supersolid phases as the anisotropy parameter is changed. The density ordering wave vectors are locked to commensurate values and jump between adjacent supersolids. In the thermodynamic limit, however, the magnitude of these jumps vanishes leading to a continuous set of novel incommensurate supersolid phases.

PACS
67.80.kb - Supersolid phases on lattices.
05.30.Jp - Boson systems.
75.40.Mg - Numerical simulation studies.

© EPLA 2009