PRESSURE CONTROL OF ORGANIC CONDUCTOR-DISCOVERY OF NEW TYPE OF NARROW GAP SEMICONDUCTORS

有机导体的压力控制——新型窄间隙半导体的发现

基本信息

批准号：
10304031
负责人：
KAJITA Koji
金额：
$ 4.1万
依托单位：
TOHO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Many organic conductors exhibit temperature-independent conductivity. Usually, they are considered to be dirty metals of which the electrical conduction is governed by impurity scattering. One of the main results of this investigation is the finding of pure organic conductors which shows temperature independent conductivity. In those conductors, both carrier density and mobility vary strongly with temperature. Nevertheless, we see temperature independent conduction because the effect of the change in the density and mobility just cancel out. Up to now, we know no other materials with such curious character both among organic and inorganic conductors. According to the density change at low temperatures, we found that they are semiconductors with extremely narrow energy gap.Organic conductors such as α-(BEDT-TTF)_2I_3, α-(BEDT-TSeF)_2I_3, O-(BEDT-TTF)_2I_3 and α-(BEDT-STF)_2I_3 belongs to this category of materials in case they are placed under high pressures.Another characteristic behavior of those materials is observed at low temperature under magnetic field. The property of carriers varies with increasing field. There are three steps of change. At low field limit, carriers have the mass of about 0.02m. where m is the free electron mass. In the intermediate field, the mass rises to a value close to m. In the high fields such as 10T, carrier mass looks to be much heavier.

许多有机导体暴露了与温度无关的电导率。通常，它们被认为是肮脏的金属，其电传导受杂质散射控制的脏金。这项研究的主要结果之一是发现纯有机导体的发现，该导体显示了温度无关的电导率。在这些导体中，载体密度和迁移率随温度而变化很大。然而，我们看到了独立的电导率，因为密度和迁移率变化的影响只是取消。到目前为止，我们都不知道有机和无机导体中具有如此奇怪性的其他材料。根据低温下的密度变化，我们发现它们是半导体，具有极狭窄的能量差异。有机导体，例如α-（bedt-ttf）_2i_3，α-（bedtt-tsef）_2i_3，o-（bedt-tttf）_2i_3 andα3andα-（bedt-the）属于CASES _2I3 IS an CASIS _2I3 IS to in CASES _2I3 ISTOS _2I3属于该分类。压力。在磁场下低温下观察到这些材料的另一个特征行为。载体的特性随田间的增加而变化。有三个变化的步骤。在低场限制下，载体的质量约为0.02m。其中m是游离电子质量。在中间场中，质量上升到接近m的值。在10T等高领域，载体质量看起来更重。