National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing, 210093, People's Republic of China.
J Phys Condens Matter. 2012 Mar 7;24(9):095302. doi: 10.1088/0953-8984/24/9/095302. Epub 2012 Feb 9.
In the framework of the Landauer-Büttiker formalism, we investigate coherent spin transport through a transverse-biased magnetic zigzag-edge graphene nanoribbon, with a temperature difference applied between the source and the drain. It is shown that a critical source temperature is needed to generate a spin-polarized current due to the presence of a forbidden transport gap. The magnitude of the obtained spin polarization exceeds 90% in a wide range of source temperatures, and its polarization direction could be changed by reversing the transverse electric field. We also find that, at fixed temperature difference, the spin-polarized current undergoes a transition from increasing to decreasing as the source temperature rises, which is attributed to the competition between the excited energy of electrons and the relative temperature difference. Moreover, by modulating the transverse electric field, the source temperature and the width of the ribbon, we can control the device to work well for generating a highly spin-polarized current.
在朗道-比尔特定律的框架下，我们研究了在源极和漏极之间施加温度差的情况下，通过横向偏置的磁锯齿边缘石墨烯纳米带的相干自旋输运。结果表明，由于存在禁止的输运间隙，需要一个临界源温度才能产生自旋极化电流。在源极温度的宽范围内，获得的自旋极化度超过 90%，并且通过反转横向电场可以改变其极化方向。我们还发现，在固定的温度差下，自旋极化电流随着源极温度的升高从增加变为减少，这归因于电子的激发能量和相对温度差之间的竞争。此外，通过调制横向电场、源极温度和带的宽度，我们可以控制器件以产生高自旋极化电流。
