Author(s)

Kateryna Foyevtsova^1,2, George A. Sawatzky^1,2

¹Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada.
²Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, BC, Canada.

In view of the growing interest in molecular orbitals (MOs) encountered in certain complex oxides, we review some of their properties from the band theory perspective and provide detailed examples based on real materials. Our discussion includes some technical aspects of identifying MOs in electronic structure calculations and considers cases when MOs can be both orthogonal and non-orthogonal. We also describe orthonormalization of MOs, a procedure converting them into Wannier functions, and discuss the problem of Wannier functions possibly being rather spatially extended and how using MO, rather than atomic orbital, based effective Hamiltonians might be a better choice in describing certain strongly correlated systems as well as systems with strong electron-phonon coupling. Furthermore, we address the problem of strongly correlated MOs and how it can be treated in band theory calculations.

Electronic Structure of Solids, Molecular Orbitals, Complex Oxides, Negative Charge-Transfer Insulators

Foyevtsova, K. and Sawatzky, G. (2019) A Band Theory Perspective on Molecular Orbitals in Complex Oxides. Journal of Modern Physics, 10, 953-965. doi: 10.4236/jmp.2019.108062.