UK-Japanese Collaboration on Current-Driven Domain Wall Dynamics

该项目将是理论（日本）和实验（英国）之间的合作。本计画将致力于研究磁性奈米线中自旋-轨道交互作用在电流驱动自旋力矩中所扮演的角色。在这里，我们将处理两个主要领域。第一个是使用自旋-轨道耦合来诱导自旋翻转散射，从而增加所谓的非绝热（β项）扭矩，该扭矩在对称性上类似场。二是研究利用自旋轨道耦合通过Rashba效应引入电流依赖的有效磁场。这两个都是凝聚态物理学中的未解之谜，因为没有预测理论可以设计出具有适当参数的材料和设备。它们还可能是实现更有效的自旋扭矩的关键，这将允许更低功率的设备操作。该项目建立在英国和日本的现有项目基础上，特别是Marrows博士持有的EPSRC资助EP/I 011668/1“多层纳米线中的电流驱动畴壁运动”和Tatara教授持有的JSPS资助科学研究（B）（资助号22340104）“自旋输运的微观理论”。在前者的实验方案和后者的分析和第一原理理论方案之间有一种天然的互补性。

The project will be a collaboration between theory (Japan) and experiment (UK). The effort of this project will be directed into study of the role of the spin-orbit interaction in current-driven spin torques in magnetic nanowires. Here we will tackle two main areas. The first is the use of spin-orbit coupling to induce spin-flip scattering and hence increase the so-called non-adiabatic (beta term) torque, which is field-like in symmetry. The second is to study the use of spin orbit coupling to introduce a current-dependent effective magnetic field through the Rashba effect. Both of these are outstanding mysteries of condensed matter physics, in that there is no predictive theory to allow materials and devices with appropriate parameters to be designed. They may also hold the key to the substantially more efficient spin-torques that will allow for lower power device operation. The project builds on existing programmes in the UK and Japan, in particular "Current-Driven Domain Wall Motion in Multilayer Nanowires" EPSRC grant EP/I011668/1 held by Dr Marrows and "Microscopic theory of spin transports", a JSPS Grant-in-Aid for Scientific Research (B) (Grant No. 22340104) held by Prof. Tatara. There is a natural complementarity between the experimental programme in the former and the programme of analytical and first-principles theory in the latter.