Spin dynamics and relaxation in graphene dictated by electron-hole puddles.
Spin dynamics and relaxation in graphene dictated by electron-hole puddles.
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DOI：
10.1038/srep21046
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发表时间：
2016-02-15
影响因子：
4.6
通讯作者：
Roche S
中科院分区：
文献类型：
--
作者：
Tuan DV;Ortmann F;Cummings AW;Soriano D;Roche S
了解清洁石墨烯中的自旋动力学和弛豫机制，以及自旋器件可以运行的上限时间和长度尺度，是实现基于石墨烯的自旋电子技术的先决条件。在这里，我们从理论上揭示了 Rashba 自旋轨道场低至几十 μeV 的不同基底上的清洁石墨烯的基本自旋弛豫机制的性质。研究发现，自旋寿命范围从 50 皮秒到几纳秒，由衬底诱导的电子空穴特性决定。描述了自旋弛豫机制从 SiO2 衬底的 Dyakonov-Perel 类型到 hBN 衬底的展宽诱导相移的交叉。自旋寿命的能量依赖性、面外和面内自旋的比率以及无序缩放提供了有关电子空穴坑存在下超净石墨烯自旋动力学和弛豫的全局图景。
The understanding of spin dynamics and relaxation mechanisms in clean graphene, and the upper time and length scales on which spin devices can operate, are prerequisites to realizing graphene-based spintronic technologies. Here we theoretically reveal the nature of fundamental spin relaxation mechanisms in clean graphene on different substrates with Rashba spin-orbit fields as low as a few tens of μeV. Spin lifetimes ranging from 50 picoseconds up to several nanoseconds are found to be dictated by substrate-induced electron-hole characteristics. A crossover in the spin relaxation mechanism from a Dyakonov-Perel type for SiO2 substrates to a broadening-induced dephasing for hBN substrates is described. The energy dependence of spin lifetimes, their ratio for spins pointing out-of-plane and in-plane, and the scaling with disorder provide a global picture about spin dynamics and relaxation in ultraclean graphene in the presence of electron-hole puddles.