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Hard-core bosons in a zig-zag optical superlattice

Dhar, Arya and Mishra, Tapan and Pai, Ramesh V and Mukerjee, Subroto and Das, BP (2013) Hard-core bosons in a zig-zag optical superlattice. In: PHYSICAL REVIEW A, 88 (5).

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Official URL: http://dx.doi.org/10.1103/PhysRevA.88.053625


We study a system of hard-core bosons at half-filling in a one-dimensional optical superlattice. The bosons are allowed to hop to nearest-and next-nearest-neighbor sites. We obtain the ground-state phase diagram as a function of microscopic parameters using the finite-size density-matrix renormalization-group method. Depending on the sign of the next-nearest-neighbor hopping and the strength of the superlattice potential the system exhibits three different phases, namely the bond-order (BO) solid, the superlattice induced Mott insulator (SLMI), and the superfluid (SF) phase. When the signs of both hopping amplitudes are the same (the unfrustratedase), the system undergoes a transition from the SF to the SLMI at a nonzero value of the superlattice potential. On the other hand, when the two amplitudes differ in sign (the frustrated case), the SF is unstable to switching on a superlattice potential and also exists only up to a finite value of the next-nearest-neighbor hopping. This part of the phase diagram is dominated by the BO phase which breaks translation symmetry spontaneously even in the absence of the superlattice potential and can thus be characterized by a bond-order parameter. The transition from BO to SLMI appears to be first order.

Item Type: Journal Article
Additional Information: copyright for this article belongs to AMER PHYSICAL SOC, USA
Department/Centre: Division of Physical & Mathematical Sciences > Physics
Date Deposited: 18 Dec 2013 11:07
Last Modified: 18 Dec 2013 11:07
URI: http://eprints.iisc.ac.in/id/eprint/47947

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