Regensburg 2019 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 20: Poster session II

MM 20.21: Poster

Dienstag, 2. April 2019, 18:30–20:00, Poster C

Metal-insulator transition due to doping triggered localization — •Martin Hoffmann¹, Florian Sipek¹, Wolfram Hergert², and Arthur Ernst^1,3 — ¹Institute for Theoretical Physics, Johannes Kepler University Linz, Austria — ²Institute of Physics, Martin Luther University Halle-Wittenberg, Germany — ³Max Planck Institute of Microstructure Physics, Halle, Germany

Recent experiments found a doping induced metal-insulator transition (MIT) in CaRu_1−xCo_xO₃ at x≈ 15 % [Adv. Sci. 5, 1700978 (2018)], which was understood in terms of a simplified model as caused by Anderson localization. We are elaborating the idea of disorder induced localization using at first a tight-binding model for CaRuO₃ (CRO). The energy-level statistics of a direct diagonalized real-space clusters with randomly distributed Co impurities showed again hints pointing to localization. The latter reduces strongly the electron diffusion and, hence, causes the MIT. In order to support that model, we used also ab initio methods to study the electronic properties in Co doped CRO. The coherent potential approximation (CPA) within the Korringa-Kohn-Rostoker Green’s function method (KKR-GF) allows the investigation of substitutional disorder. We observed strong variations in the density of states and the k-space energy landscape (Bloch spectral function) with increasing Co concentration – less s states and more d states appear at the Fermi energy. This result indicates as well the localization of electrons and a reduction of the electric current.