Spin dependent charge transfer in MoSe2/hBN/Ni hybrid structures

Abstract

We present magneto-photoluminescence measurements in a hybrid two-dimensional semiconductor/ferromagnetic structure consisting of MoSe2/hBN/Ni. When the nickel layer is magnetized, we observe circularly polarized photoluminescence of the trion peak in the MoSe2 monolayer under linearly polarized excitation. This build-up of circular polarization can reach a measured value of about 4% when the magnetization of Ni is saturated perpendicularly to the sample plane and changes its sign when the magnetization is reversed. The circular polarization decreases when the hBN barrier thickness increases. These results are interpreted in terms of a spin-dependent charge transfer between the MoSe2 monolayer and the nickel film. The build-up of circular polarization is observed up to 120 K, mainly limited by the trion emission that vanishes with temperature.