Exploitation and Exploration of Organic Superconductors

我们研究了<（TMTSF）_2> X和BEDT-TTF配合物的有机超导体以及其它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体的物理性质之间的关系，以探索新的有机超导体。本课题组从事有机超导体、有机金属和导体的合成、单晶生长、光学研究和ESR工作。至于其他研究，如NMR工作，磁阻测量，场致SDW工作，拉曼，X射线晶体学工作，X射线漫散射工作，和高压下的物理测量进行了合作与其他小组。对&lt;（TMTSF）_2&gt;超导态的质子自旋弛豫测量（NMR）<ClO_4>表明，该体系的超导电性与各向异性序参量的消失有关。 关于我们 费米面上的长直线研究了&lt;（TMTSF）_2&gt;的场致SDW相<ClO_4>，在15- 17 T和22- 25 T的磁场范围内，新发现了两种磁电阻随温度变化的结构。在常压超导体<beta>- &lt;（BEDT-TTF）_2&gt;<I_3>中观察到两个超导态（一个低态<T_c>，温度<T_c>为1.1-1.5K，一个高<T_c>态，温度<T_c>为7- 8 K）。最初<T_c>在1.3 kbar的压力下发现的高态，在移除压力后保持稳定。此外，甚至在没有施加压力的情况下也观察到了这一点。&lt;（BEDT-TTF）_2&gt;和相的ESR g值、线宽、线形和单晶自旋磁化率<alpha><beta><I_3>均具有明显的温度和角度依赖性。在这两个阶段中，在室温下观察到的Dysonian线形特征的导电电子自旋共振时，微波电场施加平行于准二维导电平面的晶体。合成了一系列新的BEDT-TTF配合物（β-<I_3>、<delta>-Au<Br_2>、-Au<Cl_2>-Au<Cl_4>、-Cu &lt;（SCN）_2&gt;等）。并对其晶体结构和物理性能进行了研究。合成了一系列四（正烷基硫属元素）四烃基富瓦烯（硫属元素=硫、硒、碲），并对其化学、物理和结构性质进行了研究。合成了一系列四甲基硫属元素TTF、azaTCNQ、六氯丁二烯、<F_4>TCNQ、BTDA-TCNQ、半帽<C_6><S_8>化合物的电荷转移配合物，并研究了它们的电导、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