Journal Article

FZJ-2021-04380

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Mn‐Rich MnSb 2 Te 4 : A Topological Insulator with Magnetic Gap Closing at High Curie Temperatures of 45–50 K

Wimmer, S. ; Sánchez-Barriga, J. ; Küppers, P. ; Ney, A. ; Schierle, E. ; Freyse, F. ; Caha, O. ; Michalička, J. ; Liebmann, M. ; Primetzhofer, D. ; Hoffman, M. ; Ernst, A. ; Otrokov, M. M. ; Bihlmayer, G.FZJ* ; Weschke, E. ; Lake, B. ; Chulkov, E. V. ; Morgenstern, M. ; Bauer, G. ; Springholz, G. ; Rader, O. (Corresponding author)

2021
Wiley-VCH Weinheim

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Please use a persistent id in citations: http://hdl.handle.net/2128/29375  doi:10.1002/adma.202102935

Abstract: Ferromagnetic topological insulators exhibit the quantum anomalous Hall effect, which is potentially useful for high-precision metrology, edge channel spintronics, and topological qubits. The stable 2+ state of Mn enables intrinsic magnetic topological insulators. MnBi2Te4 is, however, antiferromagnetic with 25 K Néel temperature and is strongly n-doped. In this work, p-type MnSb2Te4, previously considered topologically trivial, is shown to be a ferromagnetic topological insulator for a few percent Mn excess. i) Ferromagnetic hysteresis with record Curie temperature of 45–50 K, ii) out-of-plane magnetic anisotropy, iii) a 2D Dirac cone with the Dirac point close to the Fermi level, iv) out-of-plane spin polarization as revealed by photoelectron spectroscopy, and v) a magnetically induced bandgap closing at the Curie temperature, demonstrated by scanning tunneling spectroscopy (STS), are shown. Moreover, a critical exponent of the magnetization β ≈ 1 is found, indicating the vicinity of a quantum critical point. Ab initio calculations reveal that Mn–Sb site exchange provides the ferromagnetic interlayer coupling and the slight excess of Mn nearly doubles the Curie temperature. Remaining deviations from the ferromagnetic order open the inverted bulk bandgap and render MnSb2Te4 a robust topological insulator and new benchmark for magnetic topological insulators.

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Contributing Institute(s):

1. Quanten-Theorie der Materialien (PGI-1)
2. Quanten-Theorie der Materialien (IAS-1)
3. JARA-FIT (JARA-FIT)
4. JARA - HPC (JARA-HPC)

Research Program(s):

1. 5211 - Topological Matter (POF4-521) (POF4-521)

Appears in the scientific report 2021

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Essential Science Indicators ; IF >= 25 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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