Pressure dependence of the structural and electronic properties of the molecular superconductor, (BEDT-TTF)2Cu(NCS)2

Abstract We report the compressibility tensor calculated from the pressure dependence ( The magnitudes of the principal compressibilities ki decrease very slightly and the bulk modulus strongly increases with increasing pressure. k2 is along the crystallographic b axis. Thus, the directions of the smallest(k3) and largest (k1) are in the ac plane; on the projection along the b axis, k3 is parallel to the long axis of the molecule and corresponds to the maximum density of atoms. The crystal structure of a twinned crystal has been refined to R = 0.095. Using the atomic coordinates, the transfer integrals have been calculated; the comparison of the high and ambient pressure band structures shows that the two-dimensional character of this compound is enhanced by pressure.