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arXiv · 0909.2987

Attractive Hubbard Model on a Honeycomb Lattice

K. L. Lee·K. Bouadim·G. G. Batrouni·F. Hebert·R. T. Scalettar·C. Miniatura·B. Gremaud
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Abstract

We study the attractive fermionic Hubbard model on a honeycomb lattice using determinantal quantum Monte Carlo simulations. By increasing the interaction strength U (relative to the hopping parameter t) at half-filling and zero temperature, the system undergoes a quantum phase transition at 5.0 < U_c/t < 5.1 from a semi-metal to a phase displaying simultaneously superfluid behavior and density order. Doping away from half-filling, and increasing the interaction strength at finite but low temperature T, the system always appears to be a superfluid exhibiting a crossover between a BCS and a molecular regime. These different regimes are analyzed by studying the spectral function. The formation of pairs and the emergence of phase coherence throughout the sample are studied as U is increased and T is lowered.

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K. L. Lee, K. Bouadim, G. G. Batrouni, F. Hebert, R. T. Scalettar, C. Miniatura, B. Gremaud. 2009-09-16. Attractive Hubbard Model on a Honeycomb Lattice. https://doi.org/10.1103/physrevb.80.245118

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