Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 29: Topological Insulators
O 29.2: Vortrag
Dienstag, 1. April 2014, 10:45–11:00, GER 38
Temperature effects in soft and hard x-ray photoemission from topological insulators — •Jürgen Braun, Jan Minar, and Hubert Ebert — Dept. Chemie, LMU Universität München, Germany
A brief introduction to the theory of temperature-dependent soft and hard x-ray angle-resolved photo electron spectroscopy (SARPES, HARPES) of solid materials is given with an emphasis on the so-called one-step-model of photoemission. The main aspects of the theory [1,2] and its implementation within the Munich SPR-KKR program package [3] will be reviewed. Our method, which is based on the Coherent Potential Approximation (CPA) alloy theory (alloy analogy model), goes well beyond the simple, but standard Debye-Waller approach to photoemission by including in particular the temperature dependence of the effective photoemission matrix elements as well. This allows among others to reproduce the so called XPS- or density of states limit in angle-resolved photoemission which occurs for high photon energies and/or high temperatures due to a full Brillouin zone averaging caused by phonon scattering. First examples of soft- and hard x-ray ARPES calculations at finite temperature for W(110), Sb2Te3 and Bi2Se3 will be presented.
1. A. Gray, J. Minár, J. Braun, H. Ebert, C. S. Fadley et al., Nature Materials, 10, 759 (2011) and Nature Materials 11, 957 (2012) 2. J. Braun, J. Minár, H. Ebert et al. Phys. Rev. B 88 005400 (2013) 3. H. Ebert et al., The Munich SPR-KKR package, version 6.3, http://olymp.cup.uni-muenchen.de/ak/ebert/