Abstract
The electronic structures of quasi-one-dimensional ferrimagnetic Ca 3 Co 2 O 6 are investigated using the generalized gradient approximation (GGA) as well as the GGA plus on-site Coulomb interaction (GGA+U) scheme. GGA+U calculations reveal that the interchain ferrimagnetic Ca 3 Co 2 O 6 is a Mott-Hubbard insulator rather than a metal given from GGA. In addition, we found an on-site U induced 3z2-r2 orbital ordering on Co pri sublattice which drives the intrachain ferromagnetic coupling along c-axis. Our findings suggest that strong electron-electron correlation plays an important role in Ca 3 Co 2 O 6 . © 2010 Elsevier B.V. All rights reserved.