Resonating Valence Bonds and Mean-Field d-Wave Superconductivity in Graphite

Journal Article · Tue Apr 27 00:00:00 EDT 2010 · Submitted to Physical Review B

OSTI ID:977620

Black-Schaffer, Annica M

We investigate the possibility of inducing superconductivity in a graphite layer by electronic correlation effects. We use a phenomenological microscopic Hamiltonian which includes nearest neighbor hopping and an interaction term which explicitly favors nearest neighbor spin-singlets through the well-known resonance valence bond (RVB) character of planar organic molecules. Treating this Hamiltonian in mean-field theory, allowing for bond-dependent variation of the RVB order parameter, we show that both s- and d-wave superconducting states are possible. The d-wave solution belongs to a two-dimensional representation and breaks time reversal symmetry. At zero doping there exists a quantum critical point at the dimensionless coupling J/t = 1.91 and the s- and d-wave solutions are degenerate for low temperatures. At finite doping the d-wave solution has a significantly higher T{sub c} than the s-wave solution. By using density functional theory we show that the doping induced from sulfur absorption on a graphite layer is enough to cause an electronically driven d-wave superconductivity at graphite-sulfur interfaces. We also discuss applying our results to the case of the intercalated graphites as well as the validity of a mean-field approach.

• Research Organization: SLAC National Accelerator Laboratory (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 977620
• Report Number(s): SLAC-PUB-13986
• Journal Information: Submitted to Physical Review B, Journal Name: Submitted to Physical Review B
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ABSORPTION
FUNCTIONALS
GRAPHITE
HAMILTONIANS
MATSCI
MEAN-FIELD THEORY
ORDER PARAMETERS
RESONANCE
SULFUR
SUPERCONDUCTIVITY
SYMMETRY
VALENCE