Possible triplet p plus ip superconductivity in graphene at low filling

We study the Hubbard model on the honeycomb lattice with nearest-neighbor hopping (t > 0) and next-nearest-neighbor hopping (t' < 0). When t' < -t/6, the single-particle spectrum is featured by the continuously distributed Van Hove saddle points at the band bottom, where the density of states diverges in a power law. We investigate possible unconventional superconductivity in such systems with the Fermi level close to the band bottom by employing both random-phase-approximation and determinant quantum Monte Carlo approaches. Our study reveals a possible triplet p + ip superconductivity in this system with appropriate interactions. Our results might provide a possible route to look for triplet superconductivity with relatively high transition temperature in low-filled graphene and other similar systems.