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Low-dimensional electronic states and electron coorelation in organic conductors

有机导体中的低维电子态和电子关联

基本信息

批准号：
05402009
负责人：
KAGOSHIMA Seiichi
金额：
$ 21.06万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1996
项目状态：
已结题

项目摘要

The purpose of the present research is to clarify characteristic properties of low-dimentional electronic systems in organic conductors in the light of the Coulomb correlation between conduction electrons. Research results are summarized in two points : (1) We established the important role of high magnetic fields in studying low-dimensional electronic properties, and clarified a wide variety of electronic properties caused by the magnetic fields and theoretical basis for these phenomena. (2) We made clear the physical mechanism for a novel metal-insulator transition in some organic conductors.In the study on one-dimensional electronic properties based on TMTSF molecule it was clarified that various features of magnetoresistance as a function of the angle between the magnetic field direction and the crystalline axis are explained basically by the semi-classical theory based on the band theory and the Boltzman equation. This results gave a common basis for the study on two-dimensional e … More lectronic systems described below. With respect to the possible internal phase structure in the spin-density wave state caused by the one-dimensionality and the electron correlation our original idea to investigate this from the view point of the single particle transport under high magnetic fields revealed that a band structural change caused the change in the electronic structure in the spin-density wave state.Electronic properties of the two-dimensional systembased on BEDT-TTF molecules were studied by measurements of the angle-dependent magnetoresistance oscillations under high pressures to made clear the origin of the so-called anomalous state appearing at low temperatures. In addition we found the presence of three-dimensionality causes an anomalous increase of magnctoresistance for the magnetic filed close to the conducting plane.The metal-insulator transition in one-dimensional DCNQI conductors was found to be due to interplay among the Peierls transition of one-dimensional system, the Mott transition of highly correlated system, the Jahn-Teller effect around the copper ion, magnetic spins of copper 2*state and their entropy. Less

本研究的目的是根据传导电子之间的库仑相关性来阐明有机导体中低维电子系统的特性。研究成果概括为两点：（1）确立了强磁场在研究低维电子特性中的重要作用，阐明了磁场引起的各种电子特性以及这些现象的理论基础。 (2)阐明了一些有机导体中新型金属-绝缘体转变的物理机制。在基于TMTSF分子的一维电子特性研究中，阐明了磁阻随磁场方向与晶轴夹角变化的各种特征，基本上可以用基于能带理论和玻尔兹曼方程的半经典理论来解释。这一结果为下面描述的二维电子系统的研究提供了共同基础。对于一维和电子关联引起的自旋密度波态可能的内相结构，我们最初的想法是从高磁场下单粒子输运的角度进行研究，结果表明能带结构的变化引起了自旋密度波态电子结构的变化。通过测量角度依赖的磁阻，研究了基于BEDT-TTF分子的二维体系的电子性质高压下的振荡，以明确低温下出现的所谓异常状态的起源。此外，我们发现三维的存在会导致靠近导电平面的磁场磁阻异常增加。一维DCNQI导体中的金属-绝缘体转变是由于一维系统的Peierls转变、高度相关系统的Mott转变、铜离子周围的Jahn-Teller效应、铜的磁自旋之间的相互作用所致。 2*状态及其熵。较少的