Isothermal Compressibility and Pressure Dependence of the Crystal Structures of the Superconducting Charge-Transfer Salt κ-(BEDT-TTF)2Cu(NCS)2 [BEDT-TTF = Bis(ethylenedithio)tetrathiafulvalene]

Abstract

From the pressure dependence of the lattice parameters measured by single-crystal X-ray diffraction at room temperature, the amplitudes and directions of the principal components of the isothermal compressibility tensor of κ-(BEDT-TTF)2Cu(NCS)2, bis(ethylenedithio)tetrathiafulvalene copper dithiocyanate, have been determined from 1 × 105 Pa to 12.9 × 105 kPa. The crystal structure has been determined at 1 × 105 Pa and 7.5 × 105 kPa. From the latter, the pressure dependence of the intermolecular electron-transfer integrals and the band structure have been calculated and compared with those at 1 × 105 Pa and 15 K.