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arXiv · 2007.07637

Orbital Complexity in Intrinsic Magnetic Topological Insulators MnBi$_4$Te$_7$ and MnBi$_6$Te$_{10}$

R. C. Vidal·H. Bentmann·J. I. Facio·T. Heider·P. Kagerer·C. I. Fornari·T. R. F. Peixoto·T. Figgemeier·S. Jung·C. Cacho·B. Büchner·J. van den Brink·C. M. Schneider·L. Plucinski·E. F. Schwier·K. Shimada·M. Richter·A. Isaeva·F. Reinert
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Abstract

Using angle-resolved photoelectron spectroscopy (ARPES), we investigate the surface electronic structure of the magnetic van der Waals compounds MnBi$_4$Te$_7$ and MnBi$_6$Te$_{10}$, the $n=$~1 and 2 members of a modular (Bi$_2$Te$_3$)$_n$(MnBi$_2$Te$_4$) series, which have attracted recent interest as intrinsic magnetic topological insulators. Combining circular dichroic, spin-resolved and photon-energy-dependent ARPES measurements with calculations based on density functional theory, we unveil complex momentum-dependent orbital and spin textures in the surface electronic structure and disentangle topological from trivial surface bands. We find that the Dirac-cone dispersion of the topologial surface state is strongly perturbed by hybridization with valence-band states for Bi$_2$Te$_3$-terminated surfaces but remains preserved for MnBi$_2$Te$_4$-terminated surfaces. Our results firmly establish the topologically non-trivial nature of these magnetic van der Waals materials and indicate that the possibility of realizing a quantized anomalous Hall conductivity depends on surface termination.

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R. C. Vidal, H. Bentmann, J. I. Facio, T. Heider, P. Kagerer, C. I. Fornari, T. R. F. Peixoto, T. Figgemeier, S. Jung, C. Cacho, B. Büchner, J. van den Brink, C. M. Schneider, L. Plucinski, E. F. Schwier, K. Shimada, M. Richter, A. Isaeva, F. Reinert. 2020-07-15. Orbital Complexity in Intrinsic Magnetic Topological Insulators MnBi$_4$Te$_7$ and MnBi$_6$Te$_{10}$. https://doi.org/10.1103/physrevlett.126.176403

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