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One‐electron approach to describe charge and orbital order in Mn 2 OBO 3
Author(s) -
Matos M.,
Oliveira R. B.
Publication year - 2006
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.21032
Subject(s) - octahedron , charge (physics) , distortion (music) , chemistry , electron , lattice (music) , condensed matter physics , electronic structure , electronic band structure , charge density , crystallography , physics , computational chemistry , crystal structure , quantum mechanics , amplifier , optoelectronics , cmos , acoustics
A detailed study is performed on the band structure of the mixed‐valent Mn 2 OBO 3 warwickite, by using the high‐spin filling (hsf) scheme in the extended Hückel approach. It is found that charge ordering, found experimentally to be adopted by the compound, is associated with orbital order, represented by the presence of x 2 − y 2 holes in Mn1. The hsf scheme provides considerable improvement in the calculation of charge distribution in the material, as compared with the usual band filling scheme, with both Mn1 and Mn2 cations exhibiting positive charge. In addition, the octahedral distortion around Mn1 is correctly described as a Jahn–Teller (JT) type‐distortion. The calculated electronic band structure provides evidence that the Mn warwickite is an insulator, in agreement with experimental data. O1, connected to the JT‐like distortion of Mn1, is found to be loosely bound to the structure, as compared with other O‐atoms in the lattice, showing a favorable condition in the structural stability of the compound. Comparison is made with the mixed‐valent Fe 2 OBO 3 warwickite. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006