Electrical switching of spin-polarized light-emitting diodes based on a 2D CrI3/hBN/WSe2 heterostructure

TL;DR

This paper reports an atomically thin spin-LED device using a heterostructure of monolayer WSe2 and antiferromagnetic CrI3, demonstrating electrical control of circular polarization without magnetic fields, advancing spintronic optoelectronic applications.

Contribution

It introduces a novel 2D heterostructure-based spin-LED with electrical tunability of light helicity, enabling on-demand control of circular polarization.

Findings

Electrical tuning of polarization sign achieved.

High degree of circular polarization follows CrI3 magnetic states.

Device operates without external magnetic fields.

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 WSe2 and a few-layer antiferromagnetic CrI3, separated by a thin hBN tunneling barrier. The CrI3 and hBN layers polarize the spin of the injected carriers into the WSe2. With the valley optical selection rule in the monolayer WSe2, the electroluminescence exhibits a high degree of circular polarization that follows the CrI3 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 CrI3 magnetization. Our results establish a new platform to achieve on-demand operation of nanoscale spin-LED and electrical control of helicity for device applications.