Spin transport in hydrogenated graphene
Spin transport in hydrogenated graphene
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DOI：
10.1088/2053-1583/2/2/022002
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发表时间：
2015-04
期刊：
影响因子：
5.5
通讯作者：
D. Soriano;D. V. Tuan;S. Dubois;M. Gmitra;A. Cummings;D. Kochan;F. Ortmann;J. Charlier;J. Fabian;S. Roche
中科院分区：
文献类型：
--
作者：
D. Soriano;D. V. Tuan;S. Dubois;M. Gmitra;A. Cummings;D. Kochan;F. Ortmann;J. Charlier;J. Fabian;S. Roche
本文从理论角度讨论了氢化石墨烯中自旋输运的多方面问题。目前的实验结果表明，氢化可以增加或减少自旋寿命，这需要澄清。我们首先讨论了局域−？>再杂化和sp3 ？> C-H缺陷的形成伴随着局部磁矩的形成。氢化石墨烯的第一性原理计算揭示了自旋轨道和交换耦合的强相互作用。磁散射共振的概念，最近由Kochan等人(2014年物理。通过在稀极限下的平均场近似中的自洽Hubbard模型描述局域磁性，重新考察了Rev. Lett. 112 116602)，而使用有效的实空间N阶波包传播方法计算了自旋松弛长度和输运时间。当氢杂质含量为1ppm时，得到了典型的自旋寿命约为1ns（对应于输运时间约为50ps），并用Elliott-Yafet机制描述了自旋寿命随杂质密度的变化规律。这加强了局部缺陷引起的磁性可能是清洁石墨烯极限中大量自旋极化损失的起源的说法。
In this review we discuss the multifaceted problem of spin transport in hydrogenated graphene from a theoretical perspective. The current experimental findings suggest that hydrogenation can either increase or decrease spin lifetimes, which calls for clarification. We first discuss the spin–orbit coupling induced by local − ?> re-hybridization and sp 3 ?> C–H defect formation together with the formation of a local magnetic moment. First-principles calculations of hydrogenated graphene unravel the strong interplay of spin–orbit and exchange couplings. The concept of magnetic scattering resonances, recently introduced by Kochan et al (2014 Phys. Rev. Lett. 112 116602) is revisited by describing the local magnetism through the self-consistent Hubbard model in the mean field approximation in the dilute limit, while spin relaxation lengths and transport times are computed using an efficient real space order N wavepacket propagation method. Typical spin lifetimes on the order of 1 ns are obtained for 1 ppm of hydrogen impurities (corresponding to a transport time of about 50 ps), and the scaling of spin lifetimes with impurity density is described by the Elliott–Yafet mechanism. This reinforces the statement that local defect-induced magnetism can be at the origin of the substantial spin polarization loss in the clean graphene limit.