Exploitation and Exploration of Organic Superconductors

我们研究了&lt；(TMTSF)_2&GT；X和BEDT-TTF络合物的有机超导体以及其他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装的物理性质之间的关系，以便探索新的有机超导体。我们的团队已经完成了有机超导体的合成、有机金属和导体的合成、单晶生长、光学研究和电子自旋共振工作。至于其他研究工作，如核磁共振工作、磁阻测量、场致SDW工作、拉曼、X射线晶体工作、X射线扩散散射工作，以及高压下的物理测量，都是与其他小组合作进行的。~lt；(TMTSF)_2&gt；&lt；ClO_4&gt；超导态的质子自旋弛豫测量表明，该体系的超导电性与各向异性有序参数Al…的消失有关费米面上有更多的长线。研究了~lt；(TMTSF)_2&gt；&lt；ClO_4&gt；的场致SDW相，在15-17T和22-25T场强范围内，新发现了磁阻曲线上的两个随温度变化的结构。此外，还发现了类Shubnikov-de Haas的小振荡，其周期和幅度表现出反常的温度和场依赖关系。在常压超导体&lt；beta&gt；-&lt；(BEDT-ttf)_2&gt；&lt；I_3&gt；中观察到两个超导态(&lt；T_c&gt；=1.1-1.5K的低态和&lt；T_c&gt；=7-8K的高&lt；T_c&gt；态)。高&lt；T_c&gt；态最初是在1.3kbar的压力下发现的，在去压后保持稳定。此外，甚至在没有施加压力的情况下也观察到了这一点。发现&lt；α&gt；和&lt；(BEDT-TTf)_2&gt；&gt；&lt；i_3&gt；单晶的电子自旋共振g值、线宽、线形和自旋磁化率都具有明显的温度和角度依赖关系。在这两个相中，当微波电场平行于晶体的准二维导电面时，在室温下观察到了传导-电子自旋共振的狄逊线形特征。新合成了一系列BEDT-TTF配合物(&lt；(Beta)&gt；‘-&lt；I_3&gt；&lt；Delta&gt；-Au&lt；Br2&gt；-Au&lt；Cl2&gt；-Au&lt；Cl4&gt；-Cu&lt；(SCN)_2&gt；等)。并对其晶体结构和物理性能进行了研究。合成了一系列tetrakis(n-alkylchalcogeno)tetrachalcogenafulvalene(硫族元素=硫、硒、碲)，并研究了它们的化学、物理和结构性质。合成了四(n-甲基硫基)-TTF、氮杂TCNQ、HCBD、&lt；F4&gt；TCNQ、BTDA-TCNQ、半封盖&lt；C6&gt；&lt；S_8&gt；化合物的电荷转移络合物，并研究了它们的导电性等物理性质和晶体结构。较少

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