First-principles modelling of spin transfer and magnetism at photo-excited two-dimensional magnets and van der Waals heterostructures

• Applicant: Dr. Junjie He
• Subject Area: Theoretical Condensed Matter Physics ; Theoretical Chemistry: Molecules, Materials, Surfaces
• Term: from 2020 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 448002124

• Final Report Year: 2023

Final Report Abstract

The recent discovery of two-dimensional (2D) magnets and the related van der Waals (vdW) heterostructures has generated a great deal of excitement over their potential for manipulation of spin or magnetism at the atomistic scale. Optically driving 2D magnetic and vdW heterostructures offers the possibility of noncontact tunability for exploring new physics and spintronic applications. This project use density functional theory (DFT) and real-time time dependent density functional theory (rt-TDDFT) to explore ultrafast optical control interlayer spin transfer and magnetic properties in a large variety of 2D magnetic vdW heterostructures. Our main results of this project include: (i) we observed that laser pulses induce significant large spin injection from ferromagnets to nonmagnetic materials layers within a few femtoseconds and identified an interfacial atom-mediated spin transfer pathway in vdW heterostructures; (ii) the laser pulse can induced antiferromagnetism-ferromagnetism magnetic state transition in 2D magnetic heterostructures via asymmetrical interlayer spin transfer; (iii) an ultrafast laser pulse can induce a ferromagnetic state in nonmagnetic MoSe2 monolayers interfaced with vdW ferromagnetic MnSe2.

Publications

• Robust Giant Magnetoresistance in 2D Van der Waals Molecular Magnetic Tunnel Junctions. ACS Applied Materials & Interfaces, 13(30), 36098-36105.
  Li, Dongzhe; Frauenheim, Thomas & He, Junjie
  
• Tuning magnetism at the two-dimensional limit: a theoretical perspective. Nanoscale, 13(47), 19812-19827.
  Li, Dongzhe; Li, Shuo; Zhong, Chengyong & He, Junjie
  
• Unravelling Photoinduced Interlayer Spin Transfer Dynamics in Two-Dimensional Nonmagnetic-Ferromagnetic van der Waals Heterostructures. Nano Letters, 21(7), 3237-3244.
  He, Junjie; Li, Shuo; Bandyopadhyay, Arkamita & Frauenheim, Thomas
  
• Light-Controlled Ultrafast Magnetic State Transition in Antiferromagnetic–Ferromagnetic van der Waals Heterostructures. The Journal of Physical Chemistry Letters, 13(26), 6223-6229.
  Li, Shuo; Zhou, Liujiang; Frauenheim, Thomas & He, Junjie
  
• Ultrafast Light-Induced Ferromagnetic State in Transition Metal Dichalcogenides Monolayers. The Journal of Physical Chemistry Letters, 13(12), 2765-2771.
  He, Junjie; Li, Shuo; Zhou, Liujiang & Frauenheim, Thomas