Theory of Quantum Transport based on Spin and Orbital.

基于自旋和轨道的量子传输理论。

• 批准号: 16340097
• 负责人: MAEKAWA Sadamichi
• 金额: $ 9.92万
• 依托单位: Tohoku University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16340097/
• 关键词: Spin Current; Orbital wave; Spin charge separation; Non-linear Optics; Thermopower; Spin electronics; Oxide electronics; Transition metal oxide; 量子キュービット; モット絶縁体; 量子伝導; π接合; ジョセフソン効果

An electron has the internal degrees of freedom, spin・charge・orbital, which give rise to materials properties. The flow of charge of electrons is current, and electronics is based on the control of current. The electronics based on spin current is called spin-electronics. The dynamics of orbital is also expected in transition metal oxides.In this project, the theory of quantum transport starting with the dynamics of these internal degrees of freedom of an electron has been constructed.1.It is shown that the conversion between spin current and charge current can be obtained in a non-local spin Hall device together with an experimental group. Since the conversion is one of the Onsager reciprocal relations, it is a very basic concept in physics.2.In a device consisting of superconductor/ferromagnet/superconductor tunnel junctions, the Josephson current flowing between two superconductors has the extra phase, π. This is called the π-junction. We have proposed that a superconducting ring with π-junction may be used as a quantum computing device (qubit) without applied magnetic field.3.In several transition metal oxides such as Na_xCoO_2,we have shown that the orbital degeneracy causes an electronic lattice with is different from the crystal one. As a result, a variety of novel physical properties are expected. Based on the theory, we have formulated the anomalous Hall effect and giant thermopower observed in Na_xCoO_2.In this project, we have investigated various quantum transport phenomena starting with the internal degrees of freedom of an electron.

电子具有内部自由度，自旋，电荷，轨道，可产生材料特性。电荷流是电流的，电子设备基于电流的控制。基于自旋电流的电子被称为自旋电子学。在本项目中，量子传输理论也从这些内部电子自由度开始的电子自由度开始。1.1。它表明，旋转电流和电荷电流之间的转换可以在非局部旋转霍尔设备中与实验组一起获得。由于转换是Onsager的相互关系之一，因此它是物理学中的一个非常基本的概念。2。在由超导体/超导器/超导式隧道隧道交界器组成的设备中，两个超导体之间流动的Josephson电流具有特殊相位，π。这称为π结。我们已经提出，具有π结的超导环可以用作没有磁场的无磁场的量子计算设备（QUBIT）。3。在几种过渡金属氧化物（例如Na_xCOO_2）中，我们已经表明，轨道退化护理会导致具有与晶体的电子晶格不同。结果，预计会有各种新颖的物理特性。基于该理论，我们已经制定了在Na_xcoo_2中观察到的异常霍尔效应和巨型热电，在该项目中，我们研究了各种量子运输现象，从内部的电子自由度开始。

项目成果

Superconducting π qubit with three Josephson junctions.

具有三个约瑟夫森结的超导 π 量子位。

• 发表时间: 2006
• 期刊: Appl. Phys. Lett. 88
• 作者: T.Yamashita;S.Takahashi;S.Maekawa
• 通讯作者: S.Maekawa

Momentum Dependence of Charge Excitations in the Electron-Doped Superconductor Nd_<1.85>Ce_<0.15>CuO_4 : a Resonant Inelastic X-ray Scattering Study

电子掺杂超导体Nd_<1.85>Ce_<0.15>CuO_4中电荷激发的动量依赖性：共振非弹性X射线散射研究

• 发表时间: 2005
• 期刊: Phys.Rev.Lett. 94
• 作者: K.Ishii K.Tsutsui;Y.Endoh;T.Tohyama;S.Maekawa;M.Hoesch;K.Kuzushita;M.Tsubota;T.Inami;et al.
• 通讯作者: et al.

Fermi surface splittings in multilayered high-Tc cuprates

多层高温铜酸盐中的费米表面分裂

• 发表时间: 2006
• 期刊: Physica C 445-448
• 作者: M.Mori;T.Tohyama;S.Maekawa
• 通讯作者: S.Maekawa

Many-body effects in nanospintronics devices.

纳米自旋电子器件中的多体效应。

• 发表时间: 2004
• 期刊: J.Mag.Soc.Jpn. 28(11)
• 作者: Y.Utsumi;J.Martinek;P.Bruno;J.Barnas;S.Maekawa
• 通讯作者: S.Maekawa

Andreev reflection in ferromagnet/superconductor/ferromagnet junctions

铁磁体/超导体/铁磁体结中的安德烈夫反射

• 发表时间: 2004
• 期刊: J. Magn. Magn. Mater. 272-276
• 作者: T.Watanabe;H.Yokoyama;Y.Tanaka;J.Inoue;M.Ogata;S.Takahashi;T.Yamashita;S.Takahashi;T.Yamashita;H.Imamura;T.Yamashita;S.E.Barnes;S.Kaji;T.Yamashita;T.Yamashita;S.Kaji;T.Yamashita
• 通讯作者: T.Yamashita