A New Ambient Pressure Organic Superconductor (BEDT-TTF)2Cu(Ncs)2 with Tc above 10 K

Abstract

An ambient pressure superconductivity in (BEDT-TTF)2Cu(NCS)2 is reported. The superconducting critical temperature is the highest among the organic superconductors so far obtained (Tc=10.4 K). The salt prepared using deuterated BEDT-TTF is also an ambient pressure superconductor with a slightly higher Tc (11.0K). The crystal structure analysis and resistivity measurement revealed the highly two-dimensional nature of this salt. The temperature dependence of normal resistivity, superconducting critical field, quantum oscillation of resistivity and so on are reported down to 0.5 K and up to 13.5 T. The superconducting upper critical field shows a peculiar temperature dependence, and the parallel critical field behaviour is ascribed to the dimensional crossover effect. The quantum oscillation is understood as the Shubnikov-de Haas effect, and the possible Fermi surface is presented. The possible superconducting mechanisms are also discussed.KeywordsFermi SurfaceCritical FieldCrystal Structure AnalysisQuantum OscillationHeavy Fermion SystemThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.