Exploitation and Exploration of Organic Superconductors

我们研究了<(TMTSF)_2> X和BEDT-TTF配合物等有机超导体的化学和物理性质，目的是了解组成化合物的物理和结构性质与分子组合的物理性质之间的关系，从而探索新的有机超导体。我们的团队已经完成了有机超导体、有机金属和导体的合成、单晶生长、光学研究和ESR工作。其他研究如核磁共振工作、磁阻测量、场致SDW工作、拉曼、x射线晶体学工作、x射线漫射散射工作、高压下物理测量等都是与其他小组合作进行的。在<(TMTSF)_2> <ClO_4>超导态下的质子自旋弛豫测量（NMR）表明，该体系的超导性与各向异性序参量的消失有关。研究了<(TMTSF)_2> <ClO_4>中磁场诱导的SDW相，在15-17T和22-25T磁场范围内磁阻曲线上新发现了两个温度相关结构。此外，还发现了周期和振幅表现出异常温度和场依赖性的舒布尼科夫-德哈斯类小振荡。在< β > - <(BEDT-TTF)_2> <I_3>的常压超导体中，观察到两种超导状态（<T_c> =1.1 ~ 1.5 k的低<T_c>状态和<T_c> =7 ~ 8k的高<T_c>状态）。高<T_c>状态最初是在1.3 kbar压力下发现的，在去除压力后保持稳定。此外，即使不施加压力也能观察到这种现象。<(BEDT-TTF)_2> <I_3> < α >相和< β >相的ESR g值、线宽、线形和自旋磁化率均表现出明显的温度和角依赖性。当微波电场平行于晶体的准二维导电平面时，在室温下观察到导电-电子自旋共振的dyonian线形特征。新合成了一系列BEDT-TTF配合物(<（β)>′- <I_3>, < δ > - au <Br_2>, - au <Cl_2> - au <Cl_4>, - cu <(SCN)_2>等），并对其晶体结构和物理性质进行了研究。合成了一系列四元（n-烷基硫基）四元硫基富尔烯（硫基=硫、硒、碲），并对其化学、物理和结构性质进行了研究。合成了一系列四键（n-甲基硫基）-TTF、azaTCNQ、HCBD、<F_4> TCNQ、BTDA-TCNQ、半环<C_6> <S_8>化合物的电荷转移配合物，研究了它们的电导率、物理性质和晶体结构。少

We have studied chemical and physical properties of organic superconductors of <(TMTSF)_2> X and BEDT-TTF complexes, and other organic conductors for the purposes to understand the correlation between the physical and structural properties of the component compounds and the physical properties of the molecular assemblies in order to explore new organic superconductors. Our group has done the syntheses of organic superconductors, organic metals and conductors, single crystal growths, optical studies, and ESR works. As for the other studies such as NMR works, magnetoresistance measurements, field induced SDW works, Raman, X-ray crystallographic works, X-ray diffuse scattering works, and physical measurements under high pressure were carried out by a cooperation with the other groups. Proton spin relaxation measurement (NMR) in the superconducting state of <(TMTSF)_2> <ClO_4> revealed that the superconductivity in this system is associated with the anisotropic order parameter vanishing al … More ong lines on the Fermi surface. The field induced SDW phase in <(TMTSF)_2> <ClO_4> was studied and two temperature-dependent structures in the magnetoresistance curve were newly found in the field range of 15-17T and 22-25T. Also Shubnikov-de Haas like small oscillations whose period and amplitude showed anomalous temperature and field dependence were found. In the ambient pressure superconductor of <beta> - <(BEDT-TTF)_2> <I_3> , two superconducting states were observed (a low- <T_c> state with <T_c> =1.1-1.5K and a high <T_c> state with <T_c> =7-8K). The high <T_c> state, which was originally discovered under a pressure of 1.3 kbar, is found to remain stable after removal of pressure. Moreover it has also been observed even without application of pressure. The ESR g value, linewidth, lineshape, and spin susceptibility of single crystal of the <alpha> and <beta> phases of <(BEDT-TTF)_2> <I_3> were each found to show marked temperature and angular dependences. In both phases, a Dysonian line-shape characteristic of conduction-electron spin resonance was observed at room temperature when the microwave electric field is applied parallel to the quasi-two-dimensional conducting plane of the crystal. A number of BEDT-TTF complexes were newly synthesized ( <(beta)> '- <I_3> , <delta> -Au <Br_2> , -Au <Cl_2> -Au <Cl_4> , -Cu <(SCN)_2> etc.) and their crystal structures and physical properties were studied. A series of tetrakis(n-alkylchalcogeno)tetrachalcogenafulvalene (chalcogene=sulfur, selenium, tellurium) was synthesized and their chemical, physical, and structural properties were studied. A number of charge transfer complexes of tetrakis(n-methylchalcogeno)-TTF, azaTCNQ, HCBD, <F_4> TCNQ, BTDA-TCNQ, semicapped <C_6> <S_8> compound was synthesized and electrical conductivities other physical properties, and crystal structures of them were studied. Less