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arXiv · 1107.1903

Chiral superconductivity from repulsive interactions in doped graphene

Rahul Nandkishore·Leonid Levitov·Andrey Chubukov
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Abstract

We identify graphene as a system where chiral superconductivity can be realized. Chiral superconductivity involves a pairing gap that winds in phase around the Fermi surface, breaking time reversal symmetry. We consider a unique situation arising in graphene at a specific level of doping, where the density of states is singular, strongly enhancing the critical temperature T_c. At this doping level, the Fermi surface is nested, allowing superconductivity to emerge from repulsive electron-electron interactions. We show using a renormalization group method that superconductivity dominates over all competing orders for any choice of weak repulsive interactions. Superconductivity develops in a doubly degenerate, spin singlet channel, and a mean field calculation indicates that the superconductivity is of a chiral d+id type. We therefore predict that doped graphene can provide experimental realization of spin-singlet chiral superconductivity.

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Rahul Nandkishore, Leonid Levitov, Andrey Chubukov. 2011-09-17. Chiral superconductivity from repulsive interactions in doped graphene. https://doi.org/10.1038/nphys2208

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