Li Hai, Shao Jianmei, Yao Daoxin, Yang Guowei
State Key Laboratory of Optoelectronic Materials and Technologies, Institute of Optoelectronic and Functional Composite Materials, Nanotechnology Research Center, School of Physics and Engineering, Sun Yat-sen University , Guangzhou 510275, Guangdong, People's Republic of China.
ACS Appl Mater Interfaces. 2014 Feb 12;6(3):1759-64. doi: 10.1021/am4047602. Epub 2014 Jan 13.
Two-dimensional (2D) materials are extensively explored due to the remarkable physical property and the great potential for post-silicon electronics since the landmark achievement of graphene. The monolayer (ML) MoS2 with a direct energy gap is a typical 2D material and promising candidate for a wide range of device applications. The extensive efforts so far have focused on the optical valley control applications of ML MoS2 rather than the electrical control of spin and valley transport. However, the electrical manipulation of spin injection and transport is essential to realize practical spintronics applications. Here, we theoretically demonstrated that the valley and spin transport can be electrically manipulated by a gate voltage in a normal/ferromagnetic/normal monolayer MoS2 junction device. It was found that the fully valley- and spin-polarized conductance can be achieved due to the spin-valley coupling of valence-band edges together with the exchange field, and both the amplitude and direction of the fully spin-polarized conductance can be modulated by the gate voltage. These findings not only provided deep understanding to the basic physics in the spin and valley transport of ML MoS2 but also opened an avenue for the electrical control of valley and spin transport in monolayer dichalcogenide-based devices.
自石墨烯取得具有里程碑意义的成果以来，二维（2D）材料因其卓越的物理性能以及在后硅电子学方面的巨大潜力而受到广泛研究。具有直接能隙的单层（ML）二硫化钼是一种典型的二维材料，在广泛的器件应用中颇具潜力。迄今为止，大量的研究工作集中在单层二硫化钼的光学谷控制应用上，而非自旋和谷输运的电学控制。然而，自旋注入和输运的电学操控对于实现实际的自旋电子学应用至关重要。在此，我们从理论上证明，在正常/铁磁/正常单层二硫化钼结器件中，谷和自旋输运可通过栅极电压进行电学操控。研究发现，由于价带边缘的自旋 - 谷耦合以及交换场，可实现完全的谷极化和自旋极化电导，并且完全自旋极化电导的幅度和方向均可通过栅极电压进行调制。这些发现不仅为深入理解单层二硫化钼自旋和谷输运的基本物理原理提供了帮助，也为基于单层二硫属化物的器件中谷和自旋输运的电学控制开辟了一条途径。
