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arXiv:1109.6458 · Physical Review B

Pairing in graphene: A quantum Monte Carlo study

Tianxing Ma, Zhongbing Huang, Feiming Hu, Hai-Qing Lin

Published Sep 23, 2011• 81 citations
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Abstract

To address the issue of electron correlation driven superconductivity in graphene, we perform a systematic quantum Monte Carlo study of the pairing correlation in the $t\ensuremath{-}U\ensuremath{-}V$ Hubbard model on a honeycomb lattice. For $V=0$ and close to half filling, we find that pairing with $d+id$ (${d}_{{x}^{2}\ensuremath{-}{y}^{2}}+i{d}_{xy}^{\ensuremath{'}}$ in its specific form) symmetry dominates pairing with extended-$s$ symmetry. However, as the system size or the on-site Coulomb interaction increases, the long-range part of the $d+id$ pairing correlation decreases and tends to vanish in the thermodynamic limit. An inclusion of nearest-neighbor interaction $V$, either repulsive or attractive, has a small effect on the extended-$s$ pairing correlation, but strongly suppresses the $d+id$ pairing correlation.

DOI
10.1103/physrevb.84.121410

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