Open AccessCтруктура дефектов, электронная зонная структура и фазовый переход полупроводник--металл в кобальтите PrBaCo-=SUB=-2-=/SUB=-O-=SUB=-5.5-=/SUB=-: ab initio PAW-подход
Author(s) -
V. P. Zhukov,
Eugene V. Chulkov
Publication year - 2021
Publication title -
fizika tverdogo tela
Language(s) - English
Resource type - Journals
eISSN - 1726-7498
pISSN - 0367-3294
DOI - 10.21883/ftt.2021.03.50581.232
Subject(s) - cobaltite , antibonding molecular orbital , conductivity , condensed matter physics , fermi level , materials science , ab initio , electronic band structure , cobalt , ab initio quantum chemistry methods , semiconductor , transition metal , octahedron , electronic structure , electrical resistivity and conductivity , chemistry , crystallography , crystal structure , atomic orbital , physics , metallurgy , electron , biochemistry , optoelectronics , organic chemistry , quantum mechanics , molecule , catalysis
The calculations of electronic band structure of the cobaltite PrBaCo2O5+dfor the content of oxygen near 5.5 have been performed using the first-principle PAW method. It has been shown that the semiconductor-metal transition near 5+d=5.5 is associated with the conversion of cobalt atoms in octahedral oxygen surrounding from high to low spin state and the similar atoms in pyramidal surroundingfrom the low to high spin state. The metal conductivity appears due to raising of the energy of pyramidal Co eg antibonding states. As a result these states turn up at the Fermi level thus defining the conductivity. The effect of oxygen content deviation from 5.5 on the band structure and conductivity has been studies. It is shown that the semiconductor-metal transition can be observed in the narrow range of 5+d below 5.5.