Uniaxial Strain Orientation Dependence of Superconducting Transition Temperature (T_c) and Critical Superconducting Pressure (P_c) in β-(BDA-TTP)₂I₃

Dependence of the superconducting transition temperature (T_c) and critial superconducting pressure (P_c) of the pressure-induced superconductor β-(BDA-TTP)₂I₃ [BDA-TTP = 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene] on the orientation of uniaxial strain has been investigated. On the basis of the overlap between the upper and lower bands in the energy dispersion curve, the pressure orientation is thought to change the half-filled band to the quarter-filled one. The observed variations in T_c and P_c are explained by considering the degree of application of the pressure and the degree of contribution of the effective electronic correlation at uniaxial strains with different orientations parallel to the conducting donor layer.