Spin-Induced Linear Polarization of Excitonic Emission in Antiferromagnetic van der Waals Crystals

TL;DR

This study demonstrates the spin-dependent linear polarization of excitonic emission in antiferromagnetic NiPS3, revealing strong coupling between excitons and spins, which could advance 2D magneto-optical and spintronic applications.

Contribution

It provides the first evidence of spin-induced excitonic polarization in 2D antiferromagnetic vdW materials and shows how magnetic fields can manipulate this polarization.

Findings

Excitonic emission in NiPS3 is linearly polarized perpendicular to spin orientation.

Applying an in-plane magnetic field can control the excitonic polarization.

Strong exciton-spin coupling observed in atomically thin NiPS3 flakes.

Abstract

Antiferromagnets display enormous potential in spintronics owing to its intrinsic nature, including terahertz resonance, multilevel states, and absence of stray fields. Combining with the layered nature, van der Waals (vdW) antiferromagnets hold the promise in providing new insights and new designs in two-dimensional (2D) spintronics. The zero net magnetic moments of vdW antiferromagnets strengthens the spin stability, however, impedes the correlation between spin and other excitation elements, like excitons. Such coupling is urgently anticipated for fundamental magneto-optical studies and potential opto-spintronic devices. Here, we report an ultra-sharp excitonic emission with excellent monochromaticity in antiferromagnetic nickel phosphorus trisulfides (NiPS3) from bulk to atomically thin flakes. We prove that the linear polarization of the excitonic luminescence is perpendicular to the ordered spin orientation in NiPS3. By applying an in-plane magnetic field to alter the spin orientation, we further manipulate the excitonic emission polarization. Such strong correlation between exciton and spins provides new insights for the study of magneto-optics in 2D materials, and hence opens a path for developing opto-spintronic devices and antiferromagnet-based quantum information technologies.