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arXiv · 1904.06498

Valley-Layer Coupling: A New Design Principle for Valleytronics

Zhi-Ming Yu·Shan Guan·Xian-Lei Sheng·Weibo Gao·Shengyuan A. Yang
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Abstract

We introduce the concept of valley-layer coupling (VLC) in two-dimensional materials, where the low-energy electronic states in the emergent valleys have valley-contrasted layer polarization such that each state is spatially localized on the top or bottom super-layer. The VLC enables a direct coupling between valley and gate electric field, opening a new route towards electrically controlled valleytronics. We analyze the symmetry requirements for the system to host VLC, demonstrate our idea via first-principles calculations and model analysis of a concrete 2D material example, and show that an electric, continuous, wide-range, and switchable control of valley polarization can be achieved by VLC. Furthermore, we find that systems with VLC can exhibit other interesting physics, such as valley-contrasting linear dichroism and optical selection of the electric polarization of interlayer excitons.

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Zhi-Ming Yu, Shan Guan, Xian-Lei Sheng, Weibo Gao, Shengyuan A. Yang. 2019-04-13. Valley-Layer Coupling: A New Design Principle for Valleytronics. https://doi.org/10.1103/physrevlett.124.037701

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