Regensburg 2019 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 12: HL Poster I

HL 12.50: Poster

Montag, 1. April 2019, 17:30–20:00, Poster E

Ab-Initio Electronic Structure Parameters of Thermoelectric Mg2X-Mg2Y (X,Y=Si,Ge,Sn) Substitutional Alloys — •Juan Guerra, Marcel Giar, Carsten Mahr, Michael Czerner, and Christian Heiliger — Justus Liebig University Giessen, Institut für Theoretische Physik, Giessen, Germany

There has been a wide interest in the Mg2X-Mg2Y substitutional alloys, between the isoelectronic X,Y=Si,Ge,Sn, for technological applications and fundamental research. We use the Bloch spectral density function, defined within the coherent potential approximation in the KKR method, to map an electronic band structure, to explore the electronic nature, and to extract parameters relevant for transport such as energy gaps and effective masses. We compute formation energy using total energy calculations, and we report deviations from Vegard's laws stronger when Y=Sn. General non-linear trends are reported in the measured quantitites, anisotropies in the effective masses, and the well-know convergence of the conduction bands at intermediate compositions of Mg2X_{1-x}Sn_x. We discuss the trends of our calculations, and compare them with available experimental data.