SKM 2023 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 23: Poster II

MM 23.2: Poster

Dienstag, 28. März 2023, 18:15–20:00, P2/OG1+2

Investigation of the stability for AlB₂-type transition metal diborides from electronic structure — •Nebahat Bulut and Jens Kortus — TU Bergakademie Freiberg, Institute of Theoretical Physics, Germany

Boron has huge chemical bonding diversity (metallic, ionic, and covalent bonds) because it provides fewer valence electrons compared to the number of orbitals it can form. Not surprisingly, intermetallic borides can crystallize in many different crystal symmetries, for example cubic, hexagonal or orthorhombic. The unit cell of the hexagonal AlB₂-type has two trigonal prisms in which borons are in the center surrounded by six metal atoms. Interestingly, not all twenty eight transition metals form the AlB₂-type crystal structure. The goal of the study is to understand the chemical bonding nature in detail in order to answer why some of these compounds are stable in AlB₂-type structure while others are not. We investigate the impact of the d-orbitals of the transition metals on the stability in order to provide a guideline to possible new transition metal diborides. The chemical bonding and charge transfer in these transition metal diborides is investigated by electronic structure calculations based on density functional theory as implemented in Quantum Espresso [1]. The study is focused on the analysis of the electron density together with the electron localization function (ELF) and provide thermodynamic information e.g. formation enthalpies, and mechanical properties.

[1] P. Giannozzi et al., J. Chem. Phys. 152 154105 (2020)