Optical control of the valley Zeeman effect through many-exciton interactions
Optical control of the valley Zeeman effect through many-exciton interactions
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DOI：
10.1038/s41565-020-00804-0
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发表时间：
2020-11-30
影响因子：
38.3
通讯作者：
Srivastava, Ajit
中科院分区：
文献类型：
--
作者：
Li, Weijie;Lu, Xin;Srivastava, Ajit
二维过渡金属二硫属化物（TMD）中的电荷载流子（如WSe 2）将其自旋和谷赝自旋锁定在光学可寻址索引中，该索引被提议作为未来信息处理的基础（1，2）。这种带有磁矩（3）的自旋谷指数的操纵需要调整其能量。这通常通过外部磁场（B）来实现，这实际上是麻烦的。然而，谷对比光学斯塔克效应在没有B的情况下实现谷控制，但需要大的入射功率（4，5）。因此，控制自旋谷指数的其他有效途径是期望的。在这里，我们表明，在WSe 2/MoSe 2异质双层（HBL）的层间激子（IX）之间的多体相互作用诱导的稳态谷塞曼分裂对应于B接近6 T。这种异常分裂，目前在入射功率低至微瓦，增加与功率，并能够增强，抑制，甚至翻转的B-诱导分裂的迹象。此外，谷塞曼分裂的g因子可以调节约30%的入射功率。除了valleytronics，我们的研究结果可以证明有助于实现光学非互易使用二维materials. Many体之间的相互作用的层间激子在WSe 2/MoSe 2异质双层产生一个强大的和可调的有效磁场，使谷赝自旋的控制。
Charge carriers in two-dimensional transition metal dichalcogenides (TMDs), such as WSe2, have their spin and valley-pseudospin locked into an optically addressable index that is proposed as a basis for future information processing(1,2). The manipulation of this spin-valley index, which carries a magnetic moment(3), requires tuning its energy. This is typically achieved through an external magnetic field (B), which is practically cumbersome. However, the valley-contrasting optical Stark effect achieves valley control without B, but requires large incident powers(4,5). Thus, other efficient routes to control the spin-valley index are desirable. Here we show that many-body interactions among interlayer excitons (IXs) in a WSe2/MoSe2 heterobilayer (HBL) induce a steady-state valley Zeeman splitting that corresponds to B approximate to 6 T. This anomalous splitting, present at incident powers as low as microwatts, increases with power and is able to enhance, suppress or even flip the sign of a B-induced splitting. Moreover, the g-factor of valley Zeeman splitting can be tuned by similar to 30% with incident power. In addition to valleytronics, our results could prove helpful to achieve optical non-reciprocity using two-dimensional materials.Many-body interactions amongst interlayer excitons in a WSe2/MoSe2 heterobilayer give rise to a strong and tunable effective magnetic field enabling the control of the valley pseudospin.