title: Spin-controlled Mott-Hubbard bands in LaMnO3 probed by optical ellipsometry.
abstract: Spectral ellipsometry is used to determine the dielectric function of an untwinned crystal of LaMnO3 in the range 0.5-5.6 eV at temperatures 50<or=T<or=300 K. A pronounced redistribution of spectral weight is found at the Ne el temperature T(N)=140 K. The anisotropy of the spectral weight transfer matches the magnetic ordering pattern. A superexchange model quantitatively describes spectral weight transfer induced by spin correlations. This analysis implies that the lowest-energy transitions around 2 eV are intersite d-d transitions, and that LaMnO3 is a Mott-Hubbard insulator.
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: N N
authors.initials: NN
authors.lastname: Kovaleva
authors.forename: A V
authors.initials: AV
authors.lastname: Boris
authors.forename: C
authors.initials: C
authors.lastname: Bernhard
authors.forename: A
authors.initials: A
authors.lastname: Kulakov
authors.forename: A
authors.initials: A
authors.lastname: Pimenov
authors.forename: A M
authors.initials: AM
authors.lastname: Balbashov
authors.forename: G
authors.initials: G
authors.lastname: Khaliullin
authors.forename: B
authors.initials: B
authors.lastname: Keimer