Robust optical emission polarization in MoS2 monolayers through selective valley excitation

TL;DR

This paper demonstrates highly polarized optical emission in monolayer MoS2 through selective valley excitation, maintaining polarization at room temperature and under magnetic fields, highlighting robust valley control in 2D materials.

Contribution

It reveals that monolayer MoS2 exhibits near 90% polarized emission at low temperature and retains significant polarization at room temperature, showing robust valley polarization.

Findings

Near 90% polarization at 4K

40% polarization at 300K

Polarization remains stable under 9T magnetic field

Abstract

We report polarization resolved photoluminescence from monolayer MoS2, a two-dimensional, non-centrosymmetric crystal with direct energy gaps at two different valleys in momentum space. The inherent chiral optical selectivity allows exciting one of these valleys and close to 90% polarized emission at 4K is observed with 40% polarization remaining at 300K. The high polarization degree of the emission remains unchanged in transverse magnetic fields up to 9T indicating robust, selective valley excitation.