Spin relaxation in hydrogenated graphene
Spin relaxation in hydrogenated graphene
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DOI：
10.1103/physrevb.92.195408
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发表时间：
2015-11
影响因子：
3.7
通讯作者：
M. Thomsen;M. Ervasti;A. Harju;T. Pedersen
中科院分区：
文献类型：
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作者：
M. Thomsen;M. Ervasti;A. Harju;T. Pedersen
我们使用Landauer-B“uttiker方法和自旋相关的紧束缚哈密顿量计算了氢化石墨烯的自旋输运。使用这种方法的优点是它同时给出了关于薄层电阻和局域化长度以及自旋弛豫长度的信息。此外，Landauer-B“uttiker公式可以非常有效地使用递归绿色函数技术计算。先前关于氢化石墨烯自旋弛豫时间的理论结果与实验不一致。在这里，我们研究随机排列的磁矩，自旋通道之间的干扰明确包括在石墨烯中的磁缺陷。我们发现自旋弛豫长度和薄层电阻与杂质浓度几乎成线性关系。此外，氢化石墨烯中的自旋弛豫机制仅在电荷中性点附近或在高度稀释的杂质极限下是马尔可夫的。
We calculate the spin transport of hydrogenated graphene using the Landauer-B\"uttiker formalism with a spin-dependent tight-binding Hamiltonian. The advantages of using this method is that it simultaneously gives information on sheet resistance and localization length as well as spin relaxation length. Furthermore, the Landauer-B\"uttiker formula can be computed very efficiently using the recursive Green's function technique. Previous theoretical results on spin relaxation time in hydrogenated graphene have not been in agreement with experiments. Here, we study magnetic defects in graphene with randomly aligned magnetic moments, where interference between spin-channels is explicitly included. We show that the spin relaxation length and sheet resistance scale nearly linearly with the impurity concentration. Moreover, the spin relaxation mechanism in hydrogenated graphene is Markovian only near the charge neutrality point or in the highly dilute impurity limit.