Intermixing-driven surface and bulk ferromagnetism in the quantum anomalous Hall candidate MnBi$_6$Te$_{10}$

Autor: Tcakaev, Abdul V., Rubrecht, Bastian, Facio, Jorge I., Zabolotnyy, Volodymyr B., Corredor, Laura T., Folkers, Laura C., Kochetkova, Ekaterina, Peixoto, Thiago R. F., Kagerer, Philipp, Heinze, Simon, Bentmann, Hendrik, Green, Robert J., Gargiani, Pierluigi, Valvidares, Manuel, Weschke, Eugen, Haverkort, Maurits W., Reinert, Friedrich, Brink, Jeroen van den, Büchner, Bernd, Wolter, Anja U. B., Isaeva, Anna, Hinkov, Vladimir
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
Popis: The recent realizations of the quantum anomalous Hall effect (QAHE) in MnBi$_2$Te$_4$ and MnBi$_4$Te$_7$ benchmark the (MnBi$_2$Te$_4$)(Bi$_2$Te$_3$)$_n$ family as a promising hotbed for further QAHE improvements. The family owes its potential to its ferromagnetically (FM) ordered MnBi$_2$Te$_4$ septuple layers (SL). However, the QAHE realization is complicated in MnBi$_2$Te$_4$ and MnBi$_4$Te$_7$ due to the substantial antiferromagnetic (AFM) coupling between the SL. An FM state, advantageous for the QAHE, can be stabilized by interlacing the SL with an increasing number $n$ of Bi$_2$Te$_3$ layers. However, the mechanisms driving the FM state and the number of necessary QLs are not understood, and the surface magnetism remains obscure. Here, we demonstrate robust FM properties in MnBi$_6$Te$_{10}$ ($n = 2$) with $T_C \approx 12$ K and establish their origin in the Mn/Bi intermixing phenomenon by a combined experimental and theoretical study. Our measurements reveal a magnetically intact surface with a large magnetic moment, and with FM properties similar to the bulk. Our investigation thus consolidates the MnBi$_6$Te$_{10}$ system as perspective for the QAHE at elevated temperatures.
Databáze: arXiv