Premium
First principles calculations of the formation energy of Cr/Al vacancies in spinel‐type MgCr 2 O 4 and MgAl 2 O 4
Author(s) -
Moriwake Hiroki,
Tanaka Isao,
Oba Fumiyasu,
Koyama Yukinori,
Adachi Hirohiko
Publication year - 2002
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10407
Subject(s) - vacancy defect , supercell , atom (system on chip) , spinel , chemistry , frenkel defect , embedded atom model , atomic physics , crystallography , computational chemistry , materials science , molecular dynamics , physics , metallurgy , thunderstorm , meteorology , computer science , embedded system
Quantitative analysis of the formation energy of Cr vacancy in MgCr 2 O 4 was made by first principles calculation. A 56‐atom supercell was employed and relaxation of atoms within the second‐nearest‐neighbor shell of the vacancy was taken into account. The formation energy was calculated as a function of the atomic chemical potential of Cr. Theoretical formation energy of Cr vacancy in MgCr 2 O 4 shows negative values in the case of the oxidation limit of MgCr 2 O 4 , in good agreement with experimental results showing abundance of Cr vacancies when annealed in air. On the other hand, the formation energy of the Al vacancy in MgAl 2 O 4 under the same condition is as large as 4.76 eV. This also corresponds well to the experimental fact that Al vacancy does not form alone in MgAl 2 O 4 in air. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2003