Electrical switching of spin-polarized light-emitting diodes based on a 2D CrI<sub>3</sub>/hBN/WSe<sub>2</sub> heterostructure.

Dang, Jianchen; Wu, Tongyao; Yan, Shaohua; Watanabe, Kenji; Taniguchi, Takashi; Lei, Hechang; Zhang, Xiao-Xiao · Nat Commun · 2024

basic_science · Level V

Where this comes from

Abstract

Spin-polarized light-emitting diodes (spin-LEDs) convert the electronic spin information to photon circular polarization, offering potential applications including spin amplification, optical communications, and advanced imaging. The conventional control of the emitted light's circular polarization requires a change in the external magnetic field, limiting the operation conditions of spin-LEDs. Here, we demonstrate an atomically thin spin-LED device based on a heterostructure of a monolayer WSe<sub>2</sub> and a few-layer antiferromagnetic CrI<sub>3</sub>, separated by a thin hBN tunneling barrier. The CrI<sub>3</sub> and hBN layers polarize the spin of the injected carriers into the WSe<sub>2</sub>. With the valley optical selection rule in the monolayer WSe<sub>2</sub>, the electroluminescence exhibits a high degree of circular polarization that follows the CrI<sub>3</sub> magnetic states. Importantly, we show an efficient electrical tuning, including a sign reversal, of the electroluminescent circular polarization by applying an electrostatic field due to the electrical tunability of the few-layer CrI<sub>3</sub> magnetization. Our results establish a platform to achieve on-demand operation of nanoscale spin-LED and electrical control of helicity for device applications.