Sen, Arnab and Damle, Kedar and Senthil, T (2007) Superfluid insulator transitions of hard-core bosons on the checkerboard lattice. In: Physical Review B, 76 (23). 235107-1-235107-11.
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We study hard-core bosons on the checkerboard lattice with nearest-neighbor unfrustrated hopping t and "tetrahedral" plaquette charging energy U. Analytical arguments and quantum Monte Carlo simulations lead us to the conclusion that the system undergoes a zero temperature (T) quantum phase transition from a superfluid phase at small U/t to a large U/t Mott insulator phase with $\rho = 1/4$ for a range of values of the chemical potential \mu. Further, the quarter-filled insulator breaks lattice translation symmetry in a characteristic fourfold ordering pattern and occupies a lobe of finite extent in the \mu-U/t phase diagram. A quantum Monte Carlo study slightly away from the tip of the lobe provides evidence for a direct weakly first-order superfluid insulator transition away from the tip of the lobe. While analytical arguments lead us to conclude that the transition at the tip of the lobe belongs to a different Landau-forbidden second-order universality class, an extrapolation of our numerical results suggests that the size of the first-order jump does not go to zero even at the tip of the lobe.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to American Physical Society.|
|Department/Centre:||Division of Physical & Mathematical Sciences > Physics|
|Date Deposited:||18 Jul 2008|
|Last Modified:||19 Sep 2010 04:47|
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