The magnetically induced valley-spin filtering in transition metal dichalcogenide monolayers $(M{X}_2$, where $M$ = Mo, W and $X$ = S, Se, Te) promises a new paradigm in information processing. However, the detailed understanding of this effect is still limited, regarding its underlying transport processes. Herein it is suggested that the filtering mechanism can be greatly elucidated by the concept of metal-induced gap states (MIGS), appearing in the electrode-terminated $M{X}_2$ materials, i.e., the referential filter setup. In particular, the gap states are predicted here to mediate valley- and spin-resolved charge transport near the ideal electrode/$M{X}_2$ interface, and therefore to initiate filtering. It is also argued that the role of MIGS increases when the channel length is diminished, as they begin to govern the overall valley-spin transport in the tunneling regime. In what follows, the presented study yields fundamental scaling trends for the valley-spin selectivity with respect to the intrinsic physics of the filter materials. As a result, it facilitates insight into the analyzed effects and provides design guidelines toward efficient valley-spin filter devices that are based on the discussed materials or other hexagonal monolayers with a broken inversion symmetry.

中文翻译：

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过渡金属二卤化硅单层的能隙态和谷自旋滤波

过渡金属二卤化物单层中的磁感应谷自旋滤波 $（\mathrm{中号}{X}_2$，在哪里 $\mathrm{中号}$ = Mo，W和 $X$= S，Se，Te）有望在信息处理领域树立新的典范。但是，就其潜在的运输过程而言，对该效果的详细理解仍然有限。在此建议，可以通过出现在电极端接的金属感应间隙态（MIGS）的概念来极大地阐明滤波机制。$\mathrm{中号}{X}_2$材料，即参考过滤器设置。特别是，在此预测间隙状态可介导理想电极/附近的谷值和自旋分辨电荷传输$\mathrm{中号}{X}_2$接口，并因此启动过滤。也有人认为，当通道长度减小时，MIGS的作用会增强，因为它们开始控制隧道体制中的整体谷自旋运输。在下文中，提出的研究相对于过滤材料的内在物理特性，给出了谷自旋选择性的基本定标趋势。结果，它有助于深入了解所分析的效果，并为基于所讨论的材料或具有颠倒的对称性的其他六边形单分子层的高效谷自旋滤波器装置提供设计指导。