RS Fellow - EPSRC grant (2014): Mitigating spin-current relaxation in spin-orbit coupled graphene: towards spin current routing in 2D carbon

RS 研究员 - EPSRC 资助 (2014)：减轻自旋轨道耦合石墨烯中的自旋电流弛豫：实现二维碳中的自旋电流路由

基本信息

批准号：
EP/N004817/1
负责人：
Aires Ferreira
金额：
$ 33.22万
依托单位：
University of York
依托单位国家：
英国
项目类别：
Fellowship
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FN004817%2F1
关键词：
RS Fellow EPSRC grant 2014

项目摘要

Graphene has opened a new chapter in solid-state physics due its fascinating electronic properties and high potential for innovative applications in domains as diverse as flexible electronics and solar cells. One aspect of graphene research that is currently attracting much attention is in the control of a fundamental property of electrons known as spin. This dictates that an electron is always in one of two possible states, either 'up' or 'down', meaning that the electron itself could provide the basis for a binary logic bit ('0' or '1'). Devices based on such a concept promise faster processing speeds with less energy consumption than current charge-based technologies. However, the practical realisation of spin-based transistors awaits emergent nanomaterials enabling efficient manipulation of the spin state of charge currents. Graphene is one of the most promising candidates due to the fact that it entirely consists of a 2D network of carbon that is only one atom thick. This feature leads to extreme surface sensitivity and the possibility to very precisely tailor electronic, chemical, and magnetic properties through, for example, adsorption of atomic species (adatoms). We have recently predicted that adatoms leading to local enhancement of the spin-orbit coupling in graphene can drive the formation of macroscopic spin currents in the absence of magnetic fields, a phenomenon known as the spin Hall effect. An outstanding question is concerned with the main spin relaxation mechanisms that limit the lifetimes of spin signals generated through the spin Hall effect in adatom-decorated graphene. This theoretical project will employ a broad scope approach, combining analytical tools and a novel method for fully quantum transport simulations with billions of atoms, to uncover adatom decorations incorporating both robust spin current generation and spin coherence over relevant time scales. The latter is a crucial step towards the implementation of spin logic functions necessary to explore the recently discovered spin Hall effect.

石墨烯因其迷人的电子特性以及在柔性电子和太阳能电池等多种领域创新应用的巨大潜力，开启了固态物理学的新篇章。目前石墨烯研究备受关注的一个方面是控制电子的一种基本特性，即自旋。这表明电子始终处于两种可能状态之一，即“向上”或“向下”，这意味着电子本身可以为二进制逻辑位（“0”或“1”）提供基础。与当前基于充电的技术相比，基于这种概念的设备有望实现更快的处理速度和更少的能耗。然而，自旋晶体管的实际实现需要新兴的纳米材料来有效操纵充电电流的自旋状态。石墨烯是最有前途的候选者之一，因为它完全由只有一个原子厚的二维碳网络组成。这一特性导致了极高的表面敏感性，并且可以通过例如原子种类（吸附原子）的吸附来非常精确地定制电子、化学和磁性特性。我们最近预测，导致石墨烯中自旋轨道耦合局部增强的吸附原子可以在没有磁场的情况下驱动宏观自旋电流的形成，这种现象称为自旋霍尔效应。一个突出的问题涉及主要的自旋弛豫机制，该机制限制了通过吸附原子修饰的石墨烯中的自旋霍尔效应产生的自旋信号的寿命。该理论项目将采用广泛的方法，结合分析工具和一种新颖的方法，对数十亿个原子进行完全量子输运模拟，以揭示在相关时间尺度上结合强大的自旋电流生成和自旋相干性的吸附原子装饰。后者是实现探索最近发现的自旋霍尔效应所必需的自旋逻辑函数的关键一步。