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arXiv · 2006.03061

Optical control of valley Zeeman effect through many-exciton interactions

Weijie Li·Xin Lu·Jiatian Wu·Ajit Srivastava
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Abstract

Charge carriers in two-dimensional transition metal dichalcogenides (TMDs), such as WSe$_2$, have their spin and valley-pseudospin locked into an optically-addressable index that is proposed as a basis for future information processing. The manipulation of this spin-valley index requires tuning its energy, typically through external magnetic field (B), which is cumbersome. Thus, other efficient routes like all-optical control of spin-valley index are desirable. Here, we show that many-body interactions amongst interlayer excitons in WSe$_2$/MoSe$_2$ heterobilayer induce a steady-state valley Zeeman splitting corresponding to B $\sim$ 6 Tesla. This anomalous splitting, present at incident powers as low as $\mu$Ws, increases with power and enhances, suppresses or even flips the sign of a B-induced splitting. Moreover, the $\it{g}$-factor of valley Zeeman splitting can be tuned by $\sim$ 30 $\%$ with incident power. In addition to valleytronics, our results are relevant for achieving optical non-reciprocity using two-dimensional materials.

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Weijie Li, Xin Lu, Jiatian Wu, Ajit Srivastava. 2020-06-04. Optical control of valley Zeeman effect through many-exciton interactions. https://doi.org/10.1038/s41565-020-00804-0

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