paper

Correlated Dirac Particles and Superconductivity on the Honeycomb Lattice

arXiv:1301.1267 · doi:10.1103/PhysRevB.87.094521

Abstract

We investigate the properties of the nearest-neighbor singlet pairing and the emergence of d-wave superconductivity in the doped honeycomb lattice considering the limit of large interactions and the model. First, by applying a renormalized mean-field procedure as well as slave-boson theories which account for the proximity to the Mott insulating state, we confirm the emergence of d-wave superconductivity in agreement with earlier works. We show that a small but finite spin coupling between next-nearest neighbors stabilizes d-wave symmetry compared to the extended s-wave scenario. At small hole doping, to minimize energy and to gap the whole Fermi surface or all the Dirac points, the superconducting ground state is characterized by a singlet pairing assigned to one valley and a singlet pairing to the other, which then preserves time-reversal symmetry. The slightly doped situation is distinct from the heavily doped case (around 3/8 and 5/8 filling) supporting a pure chiral symmetry and breaking time-reversal symmetry. Then, we apply the functional Renormalization Group and we study in more detail the competition between antiferromagnetism and superconductivity in the vicinity of half-filling. We discuss possible applications to strongly-correlated compounds with Copper hexagonal planes such as InCuVO. Our findings are also relevant to the understanding of exotic superfluidity with cold atoms.

13 pages, 8 figures

References in corpus (34)

Correlated Dirac Particles and Superconductivity on the Honeycomb Lattice · wovepaper