The van der Waals coupling modulation is a crucial method for designing of the physical performance in bilayer transition-metal dichalcogenides. Here, we report the band evolution and quantum transport properties of twisted bilayer WSe₂ under the approach of vertical electric fields by utilizing first-principles calculations. We find that the bandgap type of bilayer WSe₂ can be transformed from indirect to direct by twisting two monolayers. The external electric field can enable the bilayer WSe₂ under six twist angles to achieve a semiconductor to metal transition. Especially, the stacking structures of 0° and 60° show transport anisotropy, and the transport performance in the zigzag direction is slightly better than that in the armchair direction. Moreover, the transport performance of the case with twisted 60° is better than that of 0° regardless of the edge direction, when an external electric field is applied. Our results are conducive to the design and application of future WSe₂-based microelectronics and optoelectronic devices.

中文翻译：

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电场作用下双层WSe2的能带演化和输运性质的界面工程

Van der Waals耦合调制是设计双层过渡金属二卤化物中物理性能的关键方法。在这里，我们通过利用第一性原理计算来报告在垂直电场的作用下扭曲双层WSe ₂的能带演化和量子输运性质。我们发现，通过扭曲两个单层，双层WSe ₂的带隙类型可以从间接转变为直接。外部电场可以使双层WSe ₂在六个扭转角下实现半导体到金属的过渡。特别是，0°和60°的堆叠结构表现出传输各向异性，并且在之字形方向上的传输性能比在扶手椅方向上的传输性能稍好。此外，当施加外部电场时，无论边缘方向如何，扭曲60°的箱子的运输性能都比0°的运输性能好。我们的结果有助于未来基于WSe ₂的微电子和光电子器件的设计和应用。