Magnetotransport and current-induced spin transfer torque in a ferromagnetically contacted graphene
Magnetotransport and current-induced spin transfer torque in a ferromagnetically contacted graphene
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铁磁接触石墨烯中的磁输运和电流感应自旋转移扭矩
DOI：
10.1088/0953-8984/22/44/445302
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发表时间：
2010-10
期刊：
影响因子：
--
通讯作者：
Zhou, Guanghui
中科院分区：
文献类型：
--
作者：
Zhou, Benhu;Chen, Xiongwen;Wang, Haiyan;Ding, Kai-He;Zhou, Guanghui
我们从理论上研究了低温下任意极化方向的两个铁磁（FM）引线之间的自旋相关输运，在石墨烯上沉积磁性绝缘体以诱导自旋上和自旋下载流子之间的交换分裂。利用标准非平衡格林函数（NGF）技术证明了当两引线平行排列的极化强度增大时，自旋向上的态密度减小，自旋向下的态密度增大。对于交换分裂周围的电子能量，自旋向上和自旋向下通道的DOS与极化无关。相反，随着极化的增加，自旋向上时电导增大，自旋向下时电导减小。有趣的是，隧道磁电阻（TMR）的大小可以随着石墨烯中交换分裂的增加而显着抑制。此外，电流诱导的自旋传递转矩（STT）与两引线磁矩之间的相对角度θ的依赖关系呈现出类似正弦的行为，并且随着极化和/或偏置电压的增加而增强。我们将这些自旋分解效应归因于石墨烯绝缘体类型性质的破坏，在自旋向上和自旋向下载流子之间发生交换分裂。
We theoretically investigate the spin-dependent transport through a graphene sheet between two ferromagnetic (FM) leads with arbitrary polarization directions at low temperatures, where a magnetic insulator is deposited on the graphene to induce an exchange splitting between spin-up and spin-down carriers. By using standard nonequilibrium Green’s function (NGF) techniques, it is demonstrated that the density of states (DOS) decreases for spin-up and increases for spin-down when the polarization strength of the two leads in parallel alignment increases. For the electron energy around the exchange splitting, the DOS for both spin-up and spin-down channels is independent of the polarization. In contrast, the conductance increases for spin-up but decreases for spin-down with an increase of the polarization. Interestingly, the magnitude of tunneling magnetoresistance (TMR) can be dramatically suppressed with the increase of the exchange splitting in graphene. Furthermore, the current-induced spin transfer torque (STT) dependence on the relative angle θ between the magnetic moments of the two leads shows a sine-like behavior and is enhanced with an increase of the polarization and/or the bias voltage. We attribute these spin-resolved effects to the breaking of the insulator-type properties of graphene with an exchange splitting between spin-up and spin-down carriers.
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DOI：
10.1140/epjb/e2009-00034-6
发表时间：
2009-02
期刊：
The European Physical Journal B
影响因子：
--
作者：
A. Saffarzadeh;M. Ghorbani Asl
通讯作者：
A. Saffarzadeh;M. Ghorbani Asl
影响因子：
3.7
作者：
X. Waintal;E. B. Myers;P. Brouwer;D. Ralph
通讯作者：
X. Waintal;E. B. Myers;P. Brouwer;D. Ralph
DOI：
10.1088/0953-8984/22/3/035301
发表时间：
2010-01
期刊：
Journal of Physics: Condensed Matter
影响因子：
--
作者：
Jiang-chai Chen;Shu-guang Cheng;S. Shen;Qing Sun
通讯作者：
Jiang-chai Chen;Shu-guang Cheng;S. Shen;Qing Sun
影响因子：
8.6
作者：
MEIR, Y;WINGREEN, NS
通讯作者：
WINGREEN, NS
影响因子：
3.7
作者：
Wei-Hua Wang;K. Pi;Yan Li;Y. Chiang;P. Wei;Jing Shi;R. Kawakami
通讯作者：
Wei-Hua Wang;K. Pi;Yan Li;Y. Chiang;P. Wei;Jing Shi;R. Kawakami