Berlin 2018 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 32: Electronic structure of surfaces: Spectroscopy, surface states I

O 32.5: Vortrag

Dienstag, 13. März 2018, 15:00–15:15, MA 004

Electronic structure of V- and Cr-doped (BiSb)₂Te₃ thin films. — •Sonja Schatz¹, Can Raphael Crespo Vidal¹, Thiago R. F. Peixoto¹, Hendrik Bentmann¹, Martin Winnerlein², Steffen Schreyeck², Charles Gould², Karl Brunner², Laurens W. Molenkamp², and Friedrich Reinert¹ — ¹Experimentelle Physik VII, Universität Würzburg, D-97074 Würzburg — ²Experimentelle Physik III, Universität Würzburg, D-97074 Würzburg

Magnetic topological insulators have received large interest in recent years, as they realize the long-sought-after quantum anomalous Hall effect. In particular, V- anc Cr-doped (Bi_xSb_1−x)₂Te₃ thin films have been reported to exhibit an insulating ferromagnetic ground state and a quantum anomalous Hall phase at low temperatures. The macroscopic magnetic properties of these films vary depending on doping-type (V vs. Cr) [1] and on the host stoichiometry parameter x. Here, we present our investigations on the electronic structure in dependence of these parameters by resonant photoelectron spectroscopy at the 2p absorption edges. We find that V 3d states are located at the Fermi level E_F, while for Cr the 3d states shift towards higher binding energies and show a vanishing density of states at E_F. We discuss possible implications on the nature of the ferromagnetic interactions in this material class.

[1] C. Z. Chang et al., Nature Materials 14, 473 (2015).

[2] T. Peixoto et al., Physical Review B 94, 195140 (2016).