Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 19: Semiconductor Substrates: Structure, Adsorption and Growth
O 19.7: Poster
Monday, March 7, 2016, 17:00–19:30, Poster A
Sub-surface Incorporation of 3d Metal Atoms Into Bi(111) Films — •N.J. Vollmers1, C. Klein2, G. Jnawali2, D. Lükermann3, C. Tegenkamp3, H. Pfnür3, M. Horn-von Hoegen2, W.G. Schmidt1, and U. Gerstmann1 — 1Theoretische Physik, Universität Paderborn — 2Fakultät für Physik, Universität Duisburg-Essen — 3Institut für Festkörperphysik, Leibniz Universität Hannover
Substrate-stabilized Bi(111) bilayers and Bi(111) surfaces have been studied intensively due to the occurrence of strongly spin-orbit split surface states. The Bi(111) surface provides a well-defined incorporation site in the first bilayer that traps highly coordinating atoms like transition metals (TMs) or noble metals [1].
Here we use density functional theory (DFT) to gain a microscopic insight into the sub-surface incorporation and its implication for the Bi surface electronic properties. The Quantum-ESPRESSO package is used for relativistic DFT calculations. Thereby, spin-orbit coupling effects are included by using a numerically efficient PAW-based implementation [2]. It is found that 3d TMs penetrate the surface barrier-free, thereby causing no morphological changes at the surface. Isolated atoms assume a seven-fold coordinated interstitial position, and provide metallic near-surface state. Furthermore, we investigate the interaction between these subsorbates by analyzing subsorbate densities up to one impurity per Bi(111) unit cell. Interestingly in comparison to the single impurity, the Bi(111) lattice is restored to its ideal form.
[1] C. Klein et al., Phys. Rev. B 91, 195441 (2015).
[2] U. Gerstmann et al., Phys. Rev. B 89, 165431 (2014).