Regensburg 2019 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 17: Nanomaterials
MM 17.1: Vortrag
Dienstag, 2. April 2019, 10:15–10:30, H46
Vacancy-controlled design of MoN/TaN superlattices — Nikola Koutná1,2, Rainer Hahn1, Jakub Zálešák3, Martin Friák2, Matthias Bartosik1, Jozef Keckes3, Mojmír Šob2, Paul Mayrhofer1, and •David Holec3 — 1Institute of Materials Science and Technology, TU Wien, Vienna, Austria — 2Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Brno, Czech Republic — 3Department of Materials Science, Montanuniversität Leoben, Leoben, Austria
Superlattices are effective though experimentally simply-enough accessible microstructural design which allows tuning phase stability and mechanical properties beyond limits of their parent phases. In this contribution we report on our first principles calculations focusing on MoN and TaN, both of which prefer vacancies in their cubic-structured bulk forms. Interestingly, the vacancies strongly segregate to the MoN phase when combined with TaN into superlattices with bi-layer periods in a nm range. This trend based on energetics is further confirmed by evaluating mechanical stability based on elastic constants as well as dynamical stability from lattice vibrations. As a results, we could predict that the most stable configuration for typical conditions during magnetron sputtering, should be MoNx/TaN system with N vacancies in the MoN phase. This theoretical prediction was experimentally confirmed by X-ray diffraction and an elemental analysis in transmission electron microscope for our reactively-sputtered superlattices.