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arXiv · 1601.02641

Expansion of a Valley-Polarized Exciton Cloud in a 2D Heterostructure

Pasqual Rivera·Kyle L. Seyler·Hongyi Yu·John R. Schaibley·Jiaqiang Yan·David G. Mandrus·Wang Yao·Xiaodong Xu
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Abstract

Heterostructures comprising different monolayer semiconductors provide a new system for fundamental science and device technologies, such as in the emerging field of valleytronics. Here, we realize valley-specific interlayer excitons in monolayer WSe2-MoSe2 vertical heterostructures. We create interlayer exciton spin-valley polarization by circularly polarized optical pumping and determine a valley lifetime of 40 nanoseconds. This long-lived polarization enables the visualization of the expansion of a valley-polarized exciton cloud over several microns. The spatial pattern of the polarization evolves into a ring with increasing exciton density, a manifestation of valley exciton exchange interactions. Our work lays a foundation for quantum optoelectronics and valleytronics based on interlayer excitons in van der Waals heterostructures.

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Pasqual Rivera, Kyle L. Seyler, Hongyi Yu, John R. Schaibley, Jiaqiang Yan, David G. Mandrus, Wang Yao, Xiaodong Xu. 2016-01-11. Expansion of a Valley-Polarized Exciton Cloud in a 2D Heterostructure. https://arxiv.org/abs/1601.02641

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