Open AccessСилицид Mg-=SUB=-2-=/SUB=-Si под давлением: результаты эволюционного поиска из первых принципов
Author(s) -
Ю.В. Луняков
Publication year - 2020
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2020.05.49248.658
Subject(s) - monoclinic crystal system , phase diagram , materials science , silicide , crystallography , hexagonal crystal system , density functional theory , high pressure , phase (matter) , crystal structure , mineralogy , metallurgy , thermodynamics , chemistry , silicon , computational chemistry , physics , organic chemistry
First-principles Density Functional Theory (DFT) evolutionary searches were carried out for magnesium silicide Mg2Si structures. The well-known hexagonal structure of P63/mmc symmetry is shown to transform to monoclinic С2/m structure under pressure Р~34 GPa. The last one is stable up to pressures P<76 GPa. The monoclinic structure is changed by orhorhombic structure Pmmm, which is stable up to pressures P~235 GPa, then losing to monoclinic structure с симметрией P2/m. The structural changes under the pressures P63/mmc → С2/m → Pmmm → Р2/m are shown at the atomic levels. Structural phase diagram of the bulk silicide Mg2Si at the pressure range 0–240 GPa is constructed.