Publication details

Mn-Rich MnSb2Te4: A Topological Insulator with Magnetic Gap Closing at High Curie Temperatures of 45-50 K

Authors

WIMMER Stefan SÁNCHEZ-BARRIGA Jaime KÜPPERS Philipp NEY Andreas SCHIERLE Enrico FREYSE Friedrich CAHA Ondřej MICHALIČKA Jan LIEBMANN Marcus PRIMETZHOFER Daniel HOFFMAN Martin ERNST Arthur OTROKOV Mikhail M. BIHLMAYER Gustav WESCHKE Eugen LAKE Bella CHULKOV Evgueni V. MORGENSTERN Markus BAUER Günther GUNTHER Gunther RADER Oliver

Year of publication 2021
Type Article in Periodical
Magazine / Source Advanced Materials
MU Faculty or unit

Faculty of Science

Citation
Web https://doi.org/10.1002/adma.202102935
Doi http://dx.doi.org/10.1002/adma.202102935
Keywords magnetic bandgap; magnetic topological insulators; magnetization; MnSb; Te-2; (4); Mn-Sb site exchange; molecular beam epitaxy
Description 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 Neel 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 beta approximate to 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.

You are running an old browser version. We recommend updating your browser to its latest version.

More info