Assembling Diverse Skyrmionic Phases in Fe3GeTe2 Monolayers. Issue 12 (10th February 2022)

• Record Type: Journal Article
• Authors: Xu, Changsong; Li, Xueyang; Chen, Peng; Zhang, Yun; Xiang, Hongjun; Bellaiche, Laurent
• Is Part Of: Advanced materials. Volume 34:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-02-10
• Subjects: Fe 3GeTe 2 -- first‐principle‐based effective Hamiltonian -- fourth order interactions -- spin invariants -- topological defects; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202107779
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: Skyrmionic magnetic states are promising in advanced spintronics. This topic is experiencing recent progress in 2D magnets, with, for example, a near 300 K Curie temperature observed in Fe3 GeTe2 . However, despite previous studies reporting skyrmions in Fe3 GeTe2, such a system remains elusive, since it has been reported to host either Néel‐type or Bloch‐type textures, while a net Dzyaloshinskii–Moriya interaction (DMI) cannot occur in this compound for symmetry reasons. It is thus desirable to develop an accurate model to deeply understand Fe3 GeTe2 . Here, a newly developed method adopting spin invariants is applied to build a first‐principle‐based Hamiltonian, which predicts colorful topological defects assembled from the unit of Bloch lines, and reveals the critical role of specific forms of fourth‐order interactions in Fe3 GeTe2 . Rather than the DMI, it is the multiple fourth‐order interactions, with symmetry and spin–orbit couplings considered, that stabilize both Néel‐type and Bloch‐type skyrmions, as well as antiskyrmions, without any preference for clockwise versus counterclockwise spin rotation. This study also demonstrates that spin invariants can be used as a general approach to study complex magnetic interactions. Abstract : Magnetic effective Hamiltonians with spin invariants, which are all the possible interaction forms allowed by symmetry, are built by a new and general developed method. Application of this method to 2D magnet Fe3 GeTe2 leads to discovery of diverse skyrmionic phases, with their origins being determined to be multiple fourth order interactions with novel expressions.