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

Isakov, Sergei V.
Chien, Hong-Chi
Wu, Jian-Jheng
Chen, Yung-Chung
Chung, Chung-Hou
Sengupta, Krishnendu
Kim, Yong Baek
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We investigate the interplay between commensurate lock-in and incommensurate supersolid phases of the hardcore 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 wavevectors 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 supersoild phases.
Comment: 5 pages, 5 figures, added new results, changed title and conclusion
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Mesoscale and Nanoscale Physics