Open AccessМикроскопическое описание механизма перехода между политипами 2H и 4H карбида кремния
Author(s) -
С.А. Кукушкин,
А.В. Осипов
Publication year - 2019
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2019.03.47230.262
Subject(s) - monoclinic crystal system , atom (system on chip) , position (finance) , symmetry (geometry) , crystallography , materials science , displacement (psychology) , ab initio , bar (unit) , molecular physics , ab initio quantum chemistry methods , plane (geometry) , atomic physics , transition state , condensed matter physics , chemistry , physics , geometry , crystal structure , molecule , computer science , psychology , biochemistry , mathematics , organic chemistry , finance , meteorology , economics , psychotherapist , embedded system , catalysis
—The mechanism of displacement of one close-packed SiC layer from one minimum position to another on the example of SiC polytype transition 2 H → 4 H has been studied by ab initio methods. It has been shown that the intermediate state with monoclinic symmetry Cm greatly facilitates this displacement breaking it into two stages. Initially, the Si atom chiefly moves, only then—mainly the C atom. In this case, the Si–C bond is significantly tilted in comparison with the initial position, which allows the reducing of the compression of the SiC bonds in the ( $$11\bar {2}0$$ ) plane. Two transition states of this process, which also possess the Cm symmetry, have been computed. It has been found that the height of the activation barrier of the process of moving the close-packed layer of SiC from one position to another is equal to 1.8 eV. The energy profile of this movement has been calculated.