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Quantum Physics of Spin Density Wave in Artificial Structures of Organic Conductors

有机导体人工结构中自旋密度波的量子物理

基本信息

批准号：
15340110
负责人：
OSADA Toshihito
金额：
$ 10.69万
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 (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15340110/
关键词：
organic conductors low-dimensional electron system spin density wave microstructure hetero-structure electric field effect magnetoresistance angular effect FET structure ヘテロ接合

项目摘要

The purpose of the present research is to fabricate artificial microstructures of organic conductors and graphite, which show spin / charge density wave transitions, and to control density wave properties by handling the spatial boundary condition. To realize the artificial microstructures, we have developed two processing techniques, electrochemical overgrowth of hetero-structures of organic conductors and micro-fabrication by oxygen plasma etching. In addition to artificial structures, we have applied strong magnetic fields or strong electric fields to localize electron motion or to introduce spatial asymmetry, respectively. The main results are as the followings.1.We have successfully grown (TMTSF)_2PF_6/(TMTSF)_2ClO_4 hetero-junctions by the electrochemical overgrowth technique, and have checked the overgrown part shows normal bulk electronic properties without any damages. However there appear many micro-cracks with the size of 0.1〜1μm around the hetero-interface. This result suggests that it is difficult to fabricate the organic hetero-structures using the electrochemical overgrowth in macroscopic scale.2.We have established the technique to fabricate the graphite thin wires by the dry etching using oxygen plasma. Using the graphite thin wire samples, in which the eddy current heating effect is suppressed by the micro-fabrication, we have performed the RF transport measurement of graphite under pulsed ultra-high magnetic fields beyond 100T generated by the single-turn coil technique. We have revealed the existence of a new anomaly around 90T by avoiding heating effect.3.We have studied the electric field effect in conducting density wave phase of α-(BEDT-TTF)_2KHg(SCN)_4. Under strong electric fields along the stacking axis, the interlayer response current shows the doubly split Lebed resonances as a function of magnetic field orientations. This new phenomena is explained by the asymmetry of electron orbits on a pair of sheetlike Fermi surfaces.

本研究的目的是制备具有自旋/电荷密度波跃迁的有机导体和石墨的人工微结构，并通过处理空间边界条件来控制密度波的性质。为了实现人造微结构，我们发展了两种加工技术：电化学超长异质结构有机导体和氧等离子体刻蚀微细加工。除了人工结构外，我们还分别应用强磁场或强电场来局部化电子运动或引入空间不对称。主要研究结果如下：利用电化学过度生长技术成功生长出了（TMTSF）_2PF_6/(TMTSF)_2ClO_4异质结，并检查了过度生长部分的体电子性能正常，无损伤。在异质界面周围出现了许多0.1 ~ 1μm大小的微裂纹。这一结果表明，在宏观尺度上利用电化学过生长法制备有机异质结构是困难的。我们建立了用氧等离子体干刻蚀法制备石墨细线的技术。利用微加工抑制涡流加热效应的石墨细丝样品，在单匝线圈技术产生的超过100T的脉冲超高磁场下，对石墨进行了射频输运测量。通过避免加热效应，我们揭示了90T附近存在一个新的异常。本文研究了α-(BEDT-TTF)_2KHg(SCN)_4导电密度波相中的电场效应。在沿叠加轴方向的强电场作用下，层间响应电流随磁场方向的变化呈现双分裂Lebed共振。这种新现象可以用一对薄片状费米表面上电子轨道的不对称性来解释。

项目成果

期刊论文数量（42）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Pulse Micromagnet for Practical High-Field Measurements

用于实际高场测量的脉冲微磁体

DOI：
发表时间：
2005
期刊：
Rev.Sci.Inst
影响因子：
0
作者：
Minato;T.;Koehler;M.;Kimura;H.;Mann;I.;Yamamoto;T;品岡寛;E.Ohmichi et al.
通讯作者：
E.Ohmichi et al.

Growth and Transport Measurement of (TMTSF)_2PF_6/(TMTSF)_2C1O_4 Hetero-Junctions

(TMTSF)_2PF_6/(TMTSF)_2C1O_4 异质结的生长和传输测量

DOI：
发表时间：
2003
期刊：
Synthetic Metals 135-136
影响因子：
0
作者：
K.Kobayashi;M.Saito;E.Ohmichi;T.Osada;E.Ohmichi;E.Ohmichi;T.Osada;M.Saito;K.Kobayashi;M.Kuraguchi;T.Osada;T.Osada;E.Ohmichi;K.Kobayashi
通讯作者：
K.Kobayashi

Transport Measurements for Low-Dimensional Conductors under Ultra-High Magnetic Fields Beyond 100T

100T以上超高磁场下低维导体的输运测量