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Charge-transfer mechanism and electronic properties of a new metallic Langumuir-Blodgett films

新型金属Langumuir-Blodgett薄膜的电荷转移机制和电子特性

基本信息

批准号：
10640556
负责人：
IZUMI Mitsuru
金额：
$ 0.64万
依托单位：
Tokyo University of Mercantile Marine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640556/
关键词：
Langmuir-Blodgett (LB) films Conducting LB films Charge-transfer complex Carrier localization Negative magnetoresistance Infrared absorption BEDO-TTF Two-dimensional electronic system ラングミュアーブロジェット(LB)膜 BEDT-TTE 金属LB膜 BEDT-TTF 気水界面

项目摘要

1. The present investigators have made a success to make a new metallic Langmuir-Blodgett films of BEDO-TTF and stearic acid showing the dc conductivity 100 S/cm at room temperature. The present molecular system forms bi-layer organization with upper stearic acid and lower BEDO-TTF layers leading the formation of charge-transfer complex as (BO)2ィイD1+ィエD1(RCOO-H..OOCR)ィイD1-1ィエD1. Consequently, it has become unnecessary neither to attach a long di-hydrocarbon chain to the electroactive molecule nor to put additional fatty acid to increase the stability.2. The LB films of BEDO-TTF and stearic acid with 1:1 mixing exhibit the logarithmic increase of the dc resistance with decreasing temperature below 120 K. As a result of the study of transverse magnetoresistance down to 1.8 K we found out the negative magnetoresistance, for which we interpreted the characteristics of the existence of weakly localized two-dimensional (2D) electronic system. A theory developed by Hikami et al. was applied to the quantitative fit to obtain several microscopic parameters govern the present single carrier quantum interference phenomena. We got the quantitative values of sheet resistance and Thouless length as a function of temperature which gives an evidence of the 2D electronic system with weal localization under the coherent regime.3. The present LB films are not superconducting but classified as a dirty metal as in graphite GIC compounds and/or semiconductor superlattice. The suppression of the localization is crucial to survey of low-temperature electronic ground state such as superconductivity with zero resistance in a macroscopic scale.

1. 目前研究人员成功制备了一种新的硬脂酸和BEDO-TTF金属Langmuir-Blodgett薄膜，在室温下具有100 S/cm的直流电导率。该分子体系由硬脂酸层和BEDO-TTF层构成双层结构，形成（BO）2 γ γ γ γ γ γ + γ γ γ γ γ γ γ γ (RCOO-H. OOCR) γ γ γ γ γ -1 γ γ γ γ γ γ γ γ。因此，既不需要在电活性分子上附加长二烃链，也不需要添加额外的脂肪酸来增加稳定性。在120 K以下，随着温度的降低，硬脂酸与BEDO-TTF的LB膜的直流电阻呈对数增长。通过对横向磁阻小于1.8 K的研究，我们发现了负磁阻，由此解释了弱局域二维电子系统存在的特征。Hikami等人开发的理论被应用于定量拟合，以获得控制当前单载流子量子干涉现象的几个微观参数。得到了薄片电阻和索利斯长度随温度变化的定量值，证明了二维电子系统在相干状态下具有良好的局部化。目前的LB薄膜不是超导的，但被归类为石墨GIC化合物和/或半导体超晶格中的脏金属。抑制局域化对于在宏观尺度上测量低温电子基态（如零电阻超导）至关重要。