Regensburg 2022 – scientific programme
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O: Fachverband Oberflächenphysik
O 73: Electronic Structure of Surfaces 1
O 73.8: Talk
Thursday, September 8, 2022, 16:45–17:00, S053
Surface doping of the MnBi2Te4 family by rubidium deposition — •Klara Volckaert1, Paulina Majchrzak1, Raphaël Dubourg1, Zhihao Jiang1, Xing-Chen Pan2, Yong Chen1, and Søren Ulstrup1 — 1Department of Physics and Astronomy, Aarhus University, Denmark — 2Advanced Institute for Materials Research, Tohoku University, Japan
Intrinsic magnetic topological insulators, in the form of MnBi2Te4, have recently been realised as a remarkable platform to study quantised magnetoelectric phenomena. Here we look into the surface electronic structure during rubidium deposition in a combined angle-resolved photoemission and core level study. We find that for MnBi2Te4, the initial electron doping effect from the adsorbed rubidium atoms is small. However, deposition on the higher stoicheometry compound MnBi4Te7 leads to a dramatic modification of the electronic structure, which is different for the surface terminated by a Bi2Te3 quintuple layer compared to a MnBi2Te4 septuple layer. Additionally, high rubidium deposition rates lead to a change of the electronic structure including a shift of the valence bands towards the Fermi level for both compounds, presumably due to Rb-Te-Bi alloying. A distinct quantization of the valence states is simultaneously observed. These results are the first to explore the tunability of electronic states the surface terminations of MnBi4Te7 with in situ alkali doping and substitution, which could modify the surface magnetic ordering.