Polarization switching and electrical control of interlayer excitons in two-dimensional van der Waals heterostructures
Polarization switching and electrical control of interlayer excitons in two-dimensional van der Waals heterostructures
复制标题
DOI：
10.1038/s41566-018-0325-y
复制
发表时间：
2019-02-01
期刊：
影响因子：
35
通讯作者：
Kis, Andras
中科院分区：
文献类型：
--
作者：
Ciarrocchi, Alberto;Unuchek, Dmitrii;Kis, Andras
基于过渡金属双硫族化合物的货车德瓦尔斯异质结构中的长寿命层间激子，以及独特的自旋谷物理，使它们成为下一代光子和谷电子器件的希望。虽然层间激子的发射特性已经被研究，但仍然缺乏对它们的谷态的有效操纵，这是信息编码的必要条件。在这里，我们展示了综合电控制层间激子在MoSe 2/WSe 2异质结构。用六方氮化硼（h-BN）封装我们的良好对准的堆叠使我们能够在圆偏振激发下解析具有相反螺旋度的两个单独的窄层间跃迁，从而保持或反转入射光的偏振。通过电控制它们的相对强度，我们实现了发射强度和波长可调的偏振开关。最后，我们观察到大的g-因素，这两个过渡的应用程序的外部磁场。这些结果被解释内的莫尔感应增亮的禁止光学跃迁的图片。控制层间激子的极化的能力是在实际器件应用中操纵谷自由度的一个步骤。
The long-lived interlayer excitons in van der Waals heterostructures based on transition-metal dichalcogenides, together with unique spin-valley physics, make them promising for next-generation photonic and valleytronic devices. Although the emission characteristics of interlayer excitons have been studied, efficient manipulation of their valley states, a necessary requirement for information encoding, is still lacking. Here, we demonstrate comprehensive electrical control of interlayer excitons in a MoSe2/WSe2 heterostructure. Encapsulation of our well-aligned stack with hexagonal boron nitride (h-BN) allows us to resolve two separate narrow interlayer transitions with opposite helicities under circularly polarized excitation, either preserving or reversing the polarization of incoming light. By electrically controlling their relative intensities, we realize a polarization switch with tunable emission intensity and wavelength. Finally, we observe large g-factors of these two transitions on application of an external magnetic field. These results are interpreted within the picture of moire-induced brightening of forbidden optical transitions. The ability to control the polarization of interlayer excitons is a step towards the manipulation of the valley degree of freedom in realistic device applications.