Superconductivity mechanism of molecular conductors through control of the dimerization and frustration

实验和理论研究了具有单向分子堆的β型有机超导体在单轴压缩下的超导转变温度（T_C）的变化。与BDA-TTP盐相反，bda - ttf盐在平行和垂直于分子堆栈的压缩中都显示出最大的T_C。对二聚和非二聚的Hubbard模型进行了T_C计算。我们发现，自旋受挫和波动效应之间的竞争导致T_C的非单调位移，二聚体模型可以很好地再现二聚性较强的bda - ttf盐中T_C的行为，而弱二聚的BDA-TTP盐中T_C的行为可以用非二聚体模型很好地再现。

We study experimentally and theoretically the shift of the superconducting transition temperature (T_C) under uniaxial compression in β-type organic superconductors possessing unidirectional molecular stacks. Contrary to the BDA-TTP salts, BEDT-TTF salts shows T_C maximum in both compressions parallel and perpendicular to the molecular stack. T_C calculations are carried out on both the dimerized and nondimerized Hubbard models. We have found that the competition between the spin frustration and the effect induced by the fluctuation causes the nonmonotonic shift of T_C and that the behavior of T_C in BEDT-TTF salts with a stronger dimerization is well reproduced by the dimer model, while that in weakly dimerized BDA-TTP salts is rather well reproduced by the nondimerized model.