title: Raman scattering in the Mott insulators LaTiO3 and YTiO3: evidence for orbital excitations.
abstract: Raman scattering is used to observe pronounced electronic excitations around 230 meV--well above the two-phonon range--in the Mott insulators LaTiO3 and YTiO3. Based on the temperature, polarization, and photon energy dependence, the modes are identified as orbital excitations. The observed profiles bear a striking resemblance to magnetic Raman modes in the insulating parent compounds of the superconducting cuprates, indicating an unanticipated universality of the electronic excitations in transition metal oxides.
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Ulrich
authors.forename: A
authors.initials: A
authors.lastname: Gössling
authors.forename: M
authors.initials: M
authors.lastname: Grüninger
authors.forename: M
authors.initials: M
authors.lastname: Guennou
authors.forename: H
authors.initials: H
authors.lastname: Roth
authors.forename: M
authors.initials: M
authors.lastname: Cwik
authors.forename: T
authors.initials: T
authors.lastname: Lorenz
authors.forename: G
authors.initials: G
authors.lastname: Khaliullin
authors.forename: B
authors.initials: B
authors.lastname: Keimer