Theory of spin relaxation and spin dynamics in silicon: from bulk to quantum dots

硅中的自旋弛豫和自旋动力学理论：从块体到量子点

• 批准号: 41099638
• 负责人: Professor Dr. Jaroslav Fabian
• 金额: --
• 依托单位: Institut für Theoretische Physik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/41099638?language=en
• 关键词: Theory; spin; relaxation; dynamics; silicon

Silicon is an ideal material for spintronics. Indeed, it exhibits among the longest spin relaxation times (more than microseconds at low temperatures), thanks to the weak spin-orbit coupling. Furthemore, a silicon spin field-effect transistor is a holy grail in the field, waiting to be realized. Both the electron spin resonance and the electric spin injection experiments have provided vital information about the spin physics in this technologically important semiconductor. In particular, we have now nice data on the temperature dependence of the spin relaxation time, from 50 K to room temperature. In the previous period of this SPP we have explained these data from theory, and developed a powerful electronic structure model for indirect optical transitions based on pseudopotentials and realistic electron-phonon coupling. In the extension we request funding for comprehensive and systematic calculations of the optical spin properties of bulk and heterostructure silicon, providing realistic picture of the Faraday effect in spin-polarized silicon. We will also compute and analyze the heterostructure dependent spin-orbit fields, considering silicon slabs and Si/Ge quantum wells, from first-principles calculations with the help of recently developed special pseudopotential techniques. We will also continue to work on the spin physics in silicon quantum dots, calculating the phonon-induced spin relaxation in single and two electron coupled dots formed in an electrostatically confined two-dimensional electron gas.

硅是自旋电子学的理想材料。事实上，由于弱的自旋轨道耦合，它表现出最长的自旋弛豫时间（在低温下超过微秒）。此外，硅自旋场效应晶体管是该领域的圣杯，等待实现。电子自旋共振和电自旋注入实验都为这种重要的半导体材料的自旋物理提供了重要的信息。特别是，我们现在有很好的数据的自旋弛豫时间的温度依赖性，从50 K到室温。在本SPP的前一阶段，我们已经从理论上解释了这些数据，并开发了一个强大的电子结构模型的基础上的赝势和现实的电子-声子耦合的间接光学跃迁。在扩展中，我们要求资助全面和系统的计算体硅和异质结硅的光学自旋特性，提供自旋极化硅中的法拉第效应的真实图像。我们还将计算和分析异质结构相关的自旋轨道场，考虑硅板和Si/Ge量子威尔斯，从第一性原理计算的帮助下，最近开发的特殊赝势技术。我们还将继续研究硅量子点中的自旋物理，计算在静电限制的二维电子气中形成的单电子和双电子耦合点中声子诱导的自旋弛豫。