Routing Valley Excitons in a Monolayer MoS2 with a Metasurface
Abstract
Excitons in monolayer transition metal dichalcogenides (TMDs) are formed at K and K' points at the boundary of the Brillouin zone. They acquire a valley degree of freedom, which may be used as a complementary platform for information transport and processing. In a different context, metasurfaces consisting of engineered arrays of polarizable inclusions have enabled the manipulation of light in unprecedented ways, and found applications in imaging, optical information processing, and cloaking. Here, we demonstrate that, by coupling a MoS2 monolayer to a suitably designed metasurface consisting of asymmetric grooves, valley polarized excitons can be sorted and spatially separated even at room temperature. Emission from valley excitons is also separated in K-space, i.e., photons with opposite helicity are emitted to different directions. Our work demonstrates that metasurfaces can facilitate valley transport and establish an interface between valleytronic and photonic devices, thus addressing outstanding challenges in the nascent field of valleytronics.
Cite
@article{arxiv.1801.06543,
title = {Routing Valley Excitons in a Monolayer MoS2 with a Metasurface},
author = {Liuyang Sun and Chun-Yuan Wang and Alexandr Krasnok and Junho Choi and Jinwei Shi and Juan Sebastian Gomez-Diaz and Andre Zepeda and Shangjr Gwo and Chih-Kang Shih and Andrea Alu and Xiaoqin Li},
journal= {arXiv preprint arXiv:1801.06543},
year = {2018}
}