Metal-nonmetal transition of hydrogenated and deuterated κ-(BEDT-TTF)2Cu[N(Cn)2]X under pressure

The pressure-temperature phase diagram covering nonmetal-metal-superconductor transition of the organic salt κ-(BEDTTTF) 2Cu[N(CN)2]Cl has been investigated by measuring the intralayer and interlayer resistivities. The anomalies in the temperature-derivative of resistivity, corresponding antiferromagnetic and weak ferromagnetic transitions, are found only for intralayer resistivity, in relation to the two-dimensional nature of the electronic phases. The salt with deuterated BEDT-TTF exhibits similar behavior with critical pressure larger by 12~15 MPa than the hydrogenated salt.