Ultrafast Laser Control of Antiferromagnetic–Ferrimagnetic Switching in Two-Dimensional Ferromagnetic Semiconductor Heterostructures

Abstract

Realizing ultrafast control of magnetization switching is of crucial importance for information processing and recording technology. Here, we explore the laser-induced spin electron excitation and relaxation dynamics processes of CrCl3/CrBr3 heterostructures with antiparallel (AP) and parallel (P) systems. Although an ultrafast demagnetization of CrCl3 and CrBr3 layers occurs in both AP and P systems, the overall magnetic order of the heterostructure remains unchanged due to the laser-induced equivalent interlayer spin electron excitation. More crucially, the interlayer magnetic order switches from antiferromagnetic (AFM) to ferrimagnetic (FiM) in the AP system once the laser pulse disappears. The microscopic mechanism underpinning this magnetization switching is dominated by the asymmetrical interlayer charge transfer combined with a spin-flip, which breaks the interlayer AFM symmetry and ultimately results in an inequivalent shift in the moment between two FM layers. Our study opens up a new idea for ultrafast laser control of magnetization switching in two-dimensional opto-spintronic devices.

Twist Angle-Dependent Intervalley Charge Carrier Transfer and Recombination in Bilayer WS2

“…Carrier recombination is modeled using decoherence-induced SH, which incorporates decoherence effects that play an important role during transitions across large energy gaps . The methods have been widely used to study carrier dynamics in various condensed matter systems, including 2D materials, ,, metal oxides, − hybrid inorganic–organic perovskites, − etc. − …”

Efficient Modeling of Quantum Dynamics of Charge Carriers in Materials Using Short Nonequilibrium Molecular Dynamics

“…These features justify the use of the classical path approximation (CPA), in which multiple and computationally expensive excited-state trajectories are replaced by a single ground-state (GS) trajectory used to sample the NA Hamiltonian . Indeed, ab initio NAMD under the CPA has proven to be a reliable tool for analyzing excited-state dynamics in a broad range of materials. − …”

Photoinduced Ultrafast Phase Transition in Bilayer CrI3

“…In recent years, a new approach has emerged that allows in situ manipulation: driving systems out of equilibrium by irradiating them with light. The femtosecond laser technique has become an appealing approach to exploring ultrafast changes and manipulations of material properties owing to the recent advances in ultrafast time-resolved diffraction techniques that combine ultrafast temporal manipulation with atomic-scale spatial resolution. − The photoexcitation induces a nonequilibrium occupation of excited electronic states, which could lead to periodic lattice distortions and expose the transient metastable states. , This approach shows promising applications in demagnetization, inducing ferromagnetism, , enhancing magnetic exchange interactions, and manipulating magnetically ordered properties in two-dimensional materials. − …”

“…14−16 The photoexcitation induces a nonequilibrium occupation of excited electronic states, which could lead to periodic lattice distortions and expose the transient metastable states. 17,18 This approach shows promising applications in demagnetization, 19 inducing ferromagnetism, 20,21 enhancing magnetic exchange interactions, 22 and manipulating magnetically ordered properties in two-dimensional materials. 23−25 Bilayer CrI 3 (BLC) can serve as a suitable platform to realize photoinduced phase transitions for manipulating magnetism.…”