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An ab initio study of mechanical and dynamical stability of MoSi2
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SYSNO ASEP 0493530 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title An ab initio study of mechanical and dynamical stability of MoSi2 Author(s) Friák, Martin (UFM-A) RID, ORCID
Holec, D. (AT)
Šob, Mojmír (UFM-A) RID, ORCIDNumber of authors 3 Source Title Journal of Alloys and Compounds. - : Elsevier - ISSN 0925-8388
Roč. 746, MAY (2018), s. 720-728Number of pages 9 s. Language eng - English Country CH - Switzerland Keywords brillouin-zone integrations ; higher-energy phases ; 1st-principles calculations ; elastic properties ; theoretical strength ; single-crystals ; electronic-structure ; transition-metals ; 1st principles ; fcc crystals ; Transition-metal silicides ; Ab initio calculations ; theoretical strength ; structural stability ; phonon spectra ; semi-metal to metal transition Subject RIV BM - Solid Matter Physics ; Magnetism OECD category Condensed matter physics (including formerly solid state physics, supercond.) R&D Projects LQ1601 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) LM2015069 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) GA16-24711S GA ČR - Czech Science Foundation (CSF) Institutional support UFM-A - RVO:68081723 UT WOS 000429170300087 EID SCOPUS 85042911985 DOI 10.1016/j.jallcom.2018.01.241 Annotation We present a quantum-mechanical study of changes in the electronic structure, total energy, elastic properties, phonon spectra and structure of molybdenum disilicide (MoSi2) with tetragonal C11(b) structure due to uniaxial strains along the [001] direction, biaxial (epitaxial) loads within the (001) plane as well as triaxial (volumetric) strains/stresses. Total energies and optimized structural parameters are computed by the Vienna Ab initio Simulation Package (VASP) using the local density approximation (LDA). When simulating extreme loading conditions that may be relevant for highly-strained regions we predict a semi-metal to metal phase transition that is connected with the onset of mechanical instability for higher values of triaxial loads as well as many other multi-axial loading conditions. The instability is assessed by both rigorous Born-Huang's criteria connected with elastic stiffness coefficients as well as by phonon spectra computed for all three straining modes. The values of theoretical tensile strength of MoSi2 for uniaxial, biaxial and triaxial loading corresponding to the first phonon instability amount to 30, 41 and 35 GPa, respectively. We show that the semi-metal to metal transition is connected with the softening of acoustic phonons at the G point rather than with the instability of other phonon modes. (C) 2018 Elsevier B.V. All rights reserved. Workplace Institute of Physics of Materials Contact Yvonna Šrámková, sramkova@ipm.cz, Tel.: 532 290 485 Year of Publishing 2019
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