Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene
Direct coupling between charge current and spin polarization by extrinsic mechanisms in graphene
复制标题
石墨烯中外在机制的充电电流与自旋极化之间的直接耦合
DOI：
10.1103/physrevb.94.085414
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发表时间：
2016
影响因子：
3.7
通讯作者：
M. Cazalilla
中科院分区：
文献类型：
--
作者：
Chunli Huang;Chunli Huang;Yidong Chong;M. Cazalilla;M. Cazalilla
自旋电子学--全电子控制电子自旋，用于量子或经典信息存储和处理--是二维材料石墨烯最有前途的应用之一。尽管原始石墨烯具有可忽略的自旋轨道耦合（SOC），但理论和实验都表明石墨烯中的SOC可以通过外在手段（例如通过吸附原子杂质的官能化）来显著增强。我们提出了一个理论的运输在石墨烯中占满自旋相干动力学的载体，包括迄今为止被忽视的自旋旋进过程中的共振散射与稀杂质。我们确定了一种新的“各向异性自旋进动散射”过程，具体到二维和非本征SOC，这有助于在石墨烯中的大电流诱导的自旋极化。该理论还产生了一个全面的描述的自旋弛豫机制在杂质修饰的石墨烯：Elliot-Yafet和Dyakonov-Perel弛豫率都存在，我们发现，后者可以占主导地位的载流子密度和杂质强度的一些选择。这为设计未来石墨烯基集成自旋电子器件提供了理论基础。
Spintronics---the all-electrical control of the electron spin for quantum or classical information storage and processing---is one of the most promising applications of the two-dimensional material graphene. Although pristine graphene has negligible spin-orbit coupling (SOC), both theory and experiment suggest that SOC in graphene can be substantially enhanced by extrinsic means, such as functionalization by adatom impurities. We present a theory of transport in graphene that accounts for the full spin-coherent dynamics of the carriers, including hitherto-neglected spin precession processes during resonant scattering with dilute impurities. We identify a novel "anisotropic spin precession scattering" process, specific to two dimensions and extrinsic SOC, which contributes to a large current-induced spin polarization in graphene. The theory also yields a comprehensive description of the spin relaxation mechanisms in impurity-decorated graphene: the Elliot-Yafet and Dyakonov-Perel relaxation rates are both present, and we find that the latter can dominate for some choices of carrier density and impurity strength. This provides theoretical foundations for designing future graphene-based integrated spintronic devices.