Control of valley degree of freedom in monolayer transition‐metal dichalcogenide (TMDC) has been realized by using optical pumping and magnetic fields. However, an electrical approach is missing and has potential for practical applications. In this paper, valley/ferroelectricity coupling is demonstrated for the first time in a monolayer WTe₂/YMnO₃ heterostructure. Tunable valley splitting by an electric field is predicted when a valley‐polarized monolayer TMDC is deposited on a multiferroic substrate. The fundamental principle behind this is an intermediate lattice–ferroelectricity coupling. An electric field changes the surface morphology of the substrate, hence the distance, that is, the exchange interaction, between the substrate and monolayer. The resulting tunable valley splitting brings a new component to electrically controlled valleytronics.

中文翻译：

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单层WTe2 / YMnO3异质结构中铁电量身定做的山谷分裂：通向电控Valleytronics的途径

通过使用光泵浦和磁场，已经实现了对单层过渡金属二硫化锡（TMDC）中谷底自由度的控制。但是，缺少电气方法，并且在实际应用中具有潜力。本文首次在单层WTe ₂ / YMnO _3中展示了谷/铁电耦合异质结构。当在多铁性基底上沉积谷极化的单层TMDC时，可以预测到电场可调谐的谷分裂。其背后的基本原理是中间的晶格-铁电耦合。电场会改变基材的表面形态，从而改变基材和单层之间的距离，即交换相互作用。由此产生的可调谐波谷分裂为电控波谷电子器件带来了新的组件。