DC conductivity, superfluid stiffness, and phase diagrams of quasi 2d organic Mott insulators (κ-BEDT)

Homes law reveals a universal scaling behavior in unconventional superconductors, relating superfluid stiffness, DC conductivity and the superconducting critical temperature. Organic superconductors are modeled by a one-band Hubbard model on a slightly different lattice than cuprates, but they are nevertheless similar. The Mott transition is pressure-induced in organics whereas it is doping-induced in cuprates. Homes law applies to both classes. Hence, reproducing this behavior is important to assess the validity of theories of superconductivity in strongly correlated materials. Using continuous-time Quantum Monte-Carlo in the hybridization expansion, we verify Homes Law in organics. We also reproduce key features of the phase diagrams of these compounds, including highly non-BCS behavior such as increasing superfluid stiffness concomitant with increasing effective mass at constant density. This shows that the interplay between the Mott transition, superconductivity, magnetic order and frustration are key ingredients for the understanding of strongly-correlated superconductors, including the cuprates.