Quantum kinetic theory of ultrafast phenomena in diluted magnetic semiconductors

稀磁半导体中超快现象的量子动力学理论

基本信息

批准号：
263274142
负责人：
Professor Dr. Vollrath Martin Axt
金额：
--
依托单位：
Lehrstuhl für Theoretische Physik III (Quantentheorie der kondensierten Materie)
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2014
资助国家：
德国
起止时间：
2013-12-31 至 2014-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/263274142?language=en
关键词：
Quantum kinetic theory ultrafast phenomena

项目摘要

This project is devoted to theoretical studies of ultrafast phenomena in diluted magnetic semiconductor (DMS) which are targeted at advancing the understanding of basic physical processes in DMS such as spin and orbital-angular-momentum transfer on ultrafast time scales. We aim to identify quantum-kinetic mechanisms that are of interest for advanced technological applications, e.g., the coherent control of magnetic properties on short times. The specific objectives of the project are three-fold. First, to elucidate the competition of the spin-orbit interaction with RKKY-type exchange interactions in the spin transfer between free carriers and magnetic impurities. Second, to explore the coherent quantum control possibilities brought about by excitation with light with orbital angular momentum (twisted light) and intense single-cycle terahertz pulses. And finally, to investigate the role of the electron-electron interaction in the decoherence processes that limit the coherent manipulation of angular-momentum transfer in DMS. The methodic starting point is a recently developed quantum kinetic density matrix description of the exchange induced spin-transfer in DMS. This theory shall be extended to include additionally the spin-orbit and electron-electron interaction as well as the coupling to twisted light. If in the course of the project it turns out to be necessary, also non-equilibrium Green's function techniques may be used. The applicability of the newly developed extended equations shall be demonstrated by numerical studies that reveal the physical implications and allow for a comparison of the predictions with realistic (existing or proposed) experimental situations.

该项目致力于在稀释的磁性半导体（DMS）中的超快现象的理论研究，这些研究旨在促进对DMS中基本物理过程的理解，例如自旋和轨道 - 角度 - 摩肌转移在超级时间尺度上。我们的目的是确定对先进技术应用感兴趣的量子运动机制，例如，短时间内对磁性的相干控制。该项目的具体目标是三倍。首先，为了阐明自旋型式交流的竞争与自由载体和磁杂质之间的自旋转移中的rkky型交换相互作用。其次，探索带有轨道角动量（扭曲的光）和强烈的单周期Terahertz脉冲的光激发带来的相干量子控制可能性。最后，要研究电子 - 电子相互作用在限制DMS角度转移相干操纵的反应过程中的作用。方法的起点是最近开发的量子动力学密度矩阵描述了DMS中诱导的自旋转移。该理论应扩展为包括自旋轨道和电子电子相互作用以及与扭曲光的耦合。如果在项目过程中，事实证明这是必要的，则还可以使用非平衡的绿色功能技术。新开发的扩展方程的适用性应通过数值研究来证明，该数值研究揭示了物理意义，并允许将预测与现实（现有或建议的）实验情况进行比较。