TY  - JOUR
AU  - Wimmer, Stefan
AU  - Sánchez-Barriga, Jaime
AU  - Küppers, Philipp
AU  - Ney, Andreas
AU  - Schierle, Enrico
AU  - Freyse, Friedrich
AU  - Caha, Ondrej
AU  - Michalička, Jan
AU  - Liebmann, Marcus
AU  - Primetzhofer, Daniel
AU  - Hoffman, Martin
AU  - Ernst, Arthur
AU  - Otrokov, Mikhail M.
AU  - Bihlmayer, Gustav
AU  - Weschke, Eugen
AU  - Lake, Bella
AU  - Chulkov, Evgueni V.
AU  - Morgenstern, Markus
AU  - Bauer, Günther
AU  - Springholz, Gunther
AU  - Rader, Oliver
TI  - Mn‐Rich MnSb 2 Te 4 : A Topological Insulator with Magnetic Gap Closing at High Curie Temperatures of 45–50 K
JO  - Advanced materials
VL  - 33
IS  - 42
SN  - 0935-9648
CY  - Weinheim
PB  - Wiley-VCH
M1  - FZJ-2021-04380
SP  - 2102935
PY  - 2021
AB  - 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.
LB  - PUB:(DE-HGF)16
C6  - pmid:34469013
UR  - <Go to ISI:>//WOS:000691903200001
DO  - DOI:10.1002/adma.202102935
UR  - https://juser.fz-juelich.de/record/902581
ER  -