Flat Bands and Wigner Crystallization in the Honeycomb Optical Lattice

Journal Article · Fri Aug 17 00:00:00 EDT 2007 · Physical Review Letters

DOI:https://doi.org/10.1103/PHYSREVLETT.99.070401· OSTI ID:21028132

Congjun, Wu ^[1]; Bergman, Doron; Balents, Leon ^[2]; Das Sarma, S ^[3]

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1. Kavli Institute for Theoretical Physics, University of California, Santa Barbara, California 93106 (United States)
2. Department of Physics, University of California, Santa Barbara, California 93106 (United States)
3. Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742 (United States)

We study the ground states of cold atoms in the tight-binding bands built from p orbitals on a two dimensional honeycomb optical lattice. The band structure includes two completely flat bands. Exact many-body ground states with on-site repulsion can be found at low particle densities, for both fermions and bosons. We find crystalline order at n=(1/6) with a {radical}(3)x{radical}(3) structure breaking a number of discrete lattice symmetries. In fermionic systems, if the repulsion is strong enough, we find the bonding strength becomes dimerized at n=(1/2). Experimental signatures of crystalline order can be detected through the noise correlations in time of flight experiments.

• OSTI ID: 21028132
• Journal Information: Physical Review Letters, Vol. 99, Issue 7; Other Information: DOI: 10.1103/PhysRevLett.99.070401; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BOSONS
CRYSTALLIZATION
EXACT SOLUTIONS
FERMIONS
GROUND STATES
HEXAGONAL LATTICES
MANY-BODY PROBLEM
TIME-OF-FLIGHT METHOD
TWO-DIMENSIONAL CALCULATIONS