In the present work we concentrate on the electronic structure of haematite
(Fe2O3) which shows two competing phenomena: correlation and hybridization
. Using the tight-binding linearized muffin-tin orbital method with the on-
site Coulomb interaction we show that, while haematite has considerable hyb
ridization between different symmetries of electronic states, its on-site C
oulomb interaction is also significant. The electronic structure is calcula
ted by using LSDA and LSDA + U approximations to take into account the exch
ange-correlation effects. The LSDA + U potential describes many basic elect
ronic properties of haematite better than the LSDA potential.