Valley polarization in MoS2 monolayers by optical pumping

TL;DR

This paper demonstrates that circularly polarized light can selectively populate valleys in MoS2 monolayers, achieving over 30% valley polarization, which is promising for valleytronics applications.

Contribution

It provides experimental evidence of valley polarization in MoS2 monolayers induced by optical pumping, a key step for valleytronics.

Findings

Over 30% valley polarization achieved

Valley polarization detected via polarization-resolved luminescence

Demonstrates potential for valley-based information encoding

Abstract

We report experimental evidences on selective occupation of the degenerate valleys in MoS2 monolayers by circularly polarized optical pumping. Over 30% valley polarization has been observed at K and K' valley via the polarization resolved luminescence spectra on pristine MoS2 monolayers. It demonstrates one viable way to generate and detect valley polarization towards the conceptual valleytronics applications with information carried by the valley index.