Berlin 2024 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 40: 2D Materials and Heterostructures: Magnetic Properties

HL 40.12: Vortrag

Donnerstag, 21. März 2024, 12:45–13:00, EW 201

Electrical Observation of Skyrmions in the Sandwich Structure Incorporating Intrinsic Ferromagnetic Topological Insulators — •Takuya Takashiro¹, Ryota Akiyama¹, Ivan Kibirev², Andrey Matetskiy², Ryosuke Nakanishi¹, Shunsuke Sato¹, Takuro Fukasawa³, Taisuke Sasaki⁴, Haruko Toyama¹, Kota Hiwatari¹, Andrey Zotov², Alexander Saranin², Toru Hirahara³, and Shuji Hasegawa¹ — ¹Department of Physics, The University of Tokyo, Tokyo, Japan — ²Vladivostok, Russia — ³Department of Physics, Tokyo Institute of Technology, Tokyo, Japan — ⁴National Institute for Materials Science, Tsukuba, Japan

A topological insulator (TI) with ferromagnetism exhibits an energy gap at the Dirac point of the topological surface state (TSS), which provides a stage for interesting phenomena such as the quantum anomalous Hall effect and magnetic vortices, skyrmions. In particular, an intrinsic ferromagnetic TI, Mn(Bi,Sb)₂Te₄, has been actively studied because of a regularly arranged Mn-monolayer which induces ferromagnetism hybridizing with the TSS. In this study, we electrically observed skyrmions emerging in Mn(Bi,Sb)₂Te₄ layers in a sandwich structure of Mn(Bi,Sb)₂Te₄/(Bi,Sb)₂Te₃/Mn(Bi,Sb)₂Te₄ and found that skyrmions were stabilized by TSSs by tuning the Fermi level and the (Bi,Sb)₂Te₃-thickness. Intriguingly, the highly-ordered Mn monolayers make the skyrmions "soft-magnetic", which is promising for such as rewritable skyrmion memory (T. Takashiro, et al. Nano Lett. 22, 881 (2022)).

Keywords: Topological insulator; Ferromagnetism; Dirac surface state; Skyrmion; Topological Hall effect