The Study of Fermi Surfaces, Field Induced Transitions and Transport Mechanisms in Organic Systems.

我们主要研究了有机导体中的三种体系。该系统包括具有相当高Tc （bbb10k）的超导体。我们已经澄清了k型物质中的费米面。我们最近报道了三种物质，并展示了可以用带计算理解的结果，包括由晶体对称性决定的细微电子结构。波段计算是建立在单个粒子图像上的。但研究发现，要理解载流子的质量，必须考虑多体效应，讨论其输运性质。该系统与著名的TMTSF系统非常相似。我们在该体系的一种物质中发现了场致跃迁。我们最近发现了另一种在环境压力下表现出磁场诱导跃迁的物质。该系统的研究尚未完成。理论界对场致相的内部结构进行了广泛的研究，因此我们认为这一体系具有重要的实验研究意义。我们还发现了该体系的超导性。与上述两种体系相比，该体系不表现出超导性。通过XANES实验表明，该方法可以获得系统特征行为的重要信息。该系统的研究包括多体效应，与上述两个系统的研究类似。我们在1992年瑞典国际会议（ICSM'92）和日本国际会议（XAFS VII）上报道了上述结果。我们正在准备关于DMET-TSeF体系中新发现现象的论文。

We have studied mainly three systems in organic conductors.1.BEDT-TTF system The system includes superconductors with fairly high Tc (>10 K). We have clarified the Fermi surfaces in the substances which are called k-type. We have newly reported on three kinds of substances, and showed the results which can be understood using band calculation including subtle electronic structures determined by crystal symmetry. The band calculation stands on the individual particle picture. But it was found that the transport property should be discussed considering the many body effect to understand the mass of the carrier.2.DMET-TSeF system This system is very similar to the famous TMTSF system. We had found the field induced transition in a substance of this system. We have recently found another substance which shows magnetic field induced transitions at ambient pressure. The study on this system is not yet completed. Theorists have been studying extensively on internal structure of the field induced phase, therefore we consider this system important for experimental investigation. We have also found superconductivity in this system.3.DCNQI system This system does not show superconductivity in contrast to the above two systems. We have shown using XANES experiments that the important information on the characteristic behaviors in this system can be obtained. The study of this system includes many-body effect which is similar to the studies of the above two systems. We have reported above results at the international conference held in 1992 in Sweden(ICSM'92), and the conference held in Japan (XAFS VII). We are preparing papers on the newly discovered phenomena in DMET-TSeF system.