Qiu X J, Cao Z Z, Cheng Y F, Qin C C
College of Electronics and Information, Hubei Key Laboratory of Intelligent Wireless Communications, South-Central University for Nationalities, Wuhan 430074, People's Republic of China.
J Phys Condens Matter. 2017 Mar 15;29(10):105301. doi: 10.1088/1361-648X/aa58c4. Epub 2017 Jan 11.
We theoretically study ballistic transport of Dirac fermions in MoS junction through arrays of barriers, of width [Formula: see text], in the presence of a tunable potential of height [Formula: see text] and an exchange field [Formula: see text]. The charge conductance as functions of [Formula: see text] and [Formula: see text], exhibits more conspicuous and sharpened oscillation as the number of barriers increase, due to the contribution of evanescent modes near the edges of the extremum conductance which are exponentially suppressed or enhanced. Furthermore, we found the valley-resolved conductance exhibits a similar oscillating behavior as the charge conductance for multiple barriers, but with inverse oscillatory phases for [Formula: see text] and [Formula: see text], accordingly, a high-efficiency fully valley polarized device is proposed in our system. Also, a perfect 100% spin polarized conductance is observed for 4 barriers and the polarized direction can be switched by changing the direction of exchange field. These findings not only benefit understanding of basic physics in monolayers MoS, but also provide us a new way to generate a pure and high-efficiency spintronics and valleytronics.
我们从理论上研究了在存在高度为[公式：见正文]的可调电势和交换场[公式：见正文]的情况下，通过宽度为[公式：见正文]的势垒阵列，狄拉克费米子在MoS结中的弹道输运。电荷电导作为[公式：见正文]和[公式：见正文]的函数，随着势垒数量的增加，由于在极值电导边缘附近的倏逝模的贡献被指数抑制或增强，呈现出更明显和尖锐的振荡。此外，我们发现谷分辨电导对于多个势垒呈现出与电荷电导类似的振荡行为，但对于[公式：见正文]和[公式：见正文]具有相反的振荡相位，因此，我们的系统中提出了一种高效的全谷极化器件。而且，对于4个势垒观察到了完美的100%自旋极化电导，并且极化方向可以通过改变交换场的方向来切换。这些发现不仅有助于理解单层MoS中的基本物理，还为我们提供了一种产生纯高效自旋电子学和谷电子学的新方法。
