Ultrafast optically induced magnetic state transition in 2D antiferromagnets

TL;DR

This study demonstrates ultrafast optical control of magnetic states in 2D antiferromagnetic heterostructures, revealing transient ferromagnetic states induced by laser pulses, advancing the understanding of opto-spintronics.

Contribution

First demonstration of optically induced transient ferromagnetic states in 2D AFM semiconductors using real-time TDDFT simulations.

Findings

Laser pulses induce significant spin injection in 2D heterostructures.

Transient ferromagnetic states are observed during photoexcitation.

Interlayer spin transfer is mediated by interface atoms.

Abstract

Manipulating spin in antiferromagnetic (AFM) materials has great potential in AFM opto-spintronics. Laser pulses can induce a transient ferromagnetic (FM) state in AFM metallic systems, but have never been proven in two-dimensional (2D) AFM semiconductors and related van der Waals (vdW) heterostructures. Here, using 2D vdW heterostructures of FM MnS2 and AFM MXenes as prototypes, we investigated optically induced interlayer spin transfer dynamics based on the real-time time-dependent density functional theory (rt-TDDFT). We observed that laser pulses induce significant spin injection and the interfacial atom-mediated spin transfer from MnS2 to Cr2CCl2. In particular, we first demonstrated the transient FM state in semiconducting AFM/FM heterostructures during photoexcited processes. Because the proximity magnetism breaks the magnetic symmetry of Cr2CCl2 in heterostructures. Our results provide the microscopic understanding for optically controlled interlayer spin dynamics in 2D magnetic heterostructures and open a new way to manipulate magnetic orders in ultrafast opto-spintronics.