Utilizing the spin or valley degree of freedom is a promising approach for realizing more energy-efficient information processing devices. Circularly polarized light can be used to generate spin/valley current in monolayer 2D transition metal dichalcogenides. We observe a geometrically dependent photocurrent in heterostructure ${{\rm MoS}_2}/{{\rm WSe}_2}$, where light with a different circular polarization generates photocurrents in opposite directions. Furthermore, we show that this photocurrent persists even at room temperature, and it can be controlled using an in-plane electric field and back gating. We explain the observed phenomena via valley-dependent valence band shift and the valley optical selection rule. This finding may facilitate the use of 2D heterostructures as a platform for opto-valleytronics and opto-spintronics devices.

中文翻译：

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范德华异质结构中的可调几何光电流

利用自旋或谷底自由度是用于实现更加节能的信息处理设备的有前途的方法。圆偏振光可用于在单层2D过渡金属二卤化金属中生成自旋/谷电流。我们观察到异质结构$ {{\ rm MoS} _2} / {{\ rm WSe} _2} $中几何相关的光电流，其中具有不同的圆偏振的光会在相反的方向上产生光电流。此外，我们表明，即使在室温下，该光电流仍然存在，并且可以使用面内电场和背栅对其进行控制。我们通过与谷有关的价带移位和谷光学选择规则来解释观察到的现象。这一发现可能有助于将2D异质结构用作光谷电子器件和光自旋电子器件的平台。