Abstract

In 2002 we combined Pauling’s resonating valence bond theory with band theory and proposed [1] a phenomenological microscopic Hamiltonian for doped graphene like systems and found high Tc superconductivity. Recently Black-Schaffer and Doniach [2] analyzed our model further and found a PT violating d + id symmetry for the order parameter. In another work [3] Meng and collaborators found Pauling’s RVB phase, interpolating a semi metal and Mott insulating antiferromagnetic phases in repulsive Hubbard model at half filling in honeycomb lattice. In this talk we discuss our recent work [4], where we replace our old model by a more realistic repulsive Hubbard model and perform an extensive, state of the art, variational Monte Carlo analysis. We find that graphene, around an optimal doping, could support Kosterlitz-Thouless superconductivity, reaching room temperature scales. How could Graphene, which is weakly or at best a moderately correlated electron system, support a high Tc superconductivity ? We suggest an adiabatic connection of our superconductivity in doped graphene to strong coupling RVB superconductivity.

1. G. Baskaran, Phys. Rev. B 65, 212505 (2002)
2. A.M. Black-Schaffer and S. Doniach, Phys. Rev. B 75, 134512 (2007)
3. Z. Y. Meng, T. Lang, S. Wessel, F. Assaad, and A. Muramatsu, Nature 464, 847 (2010)
4. S Pathak, V B Shenoy and G. Baskaran, Phys. Rev. B 81, 085431 (2010)