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colossal magneto resistance (CMR); optical conductivity; charge-transfer (CT) transitions
Abstract:
Using the Mott-Littleton approach we examine the energies of a
number of fundamental optical transitions, as well as those
involving self-trapped holes of Mn4+ and O- in LaMnO3 lattice.
The reasonable agreement with the experiment of our predicted
energies, linewidths and oscillator strengths leads us to
plausible assignments of the optical bands observed. We deduce
that the optical band near 5 eV is associated with O(2p)-Mn(3d)
transition of charge-transfer character, whereas the band near
2.3 eV is rather associated with the presence of Mn4+ and/or O-
self-trapped holes in the as-grown non-stoichiometric LaMnO3
compound. We do not exclude other contributions to the latter
band. (C) 2002 Elsevier Science B.V. All rights reserved.