title: Effect of orbital rotation and mixing on the optical properties of orthorhombic RMnO3 (R=La, Pr, Nd, Gd, and Tb).
abstract: We investigated the ab-plane absorption spectra of RMnO3 (R=La, Pr, Nd, Gd, and Tb) thin films. As the ionic radius of the R ion decreases, we observed a drastic suppression of the 2 eV peak, i.e., the intersite optical transition between spin- and orbital-aligned states across the Mott gap. We found that, in addition to orbital rotation, orbital mixing in the orbital-ordered state should play an important role in the suppression of 2 eV peak. We also found that the spectral weight of 2 eV peak is proportional to the A-type antiferromagnetic ordering temperature, which suggests that the magnetic interaction should be sensitively coupled to the orbital degree of freedom.
authors.affiliation: ReCOE & School of Physics, Seoul National University, Seoul 151-747, Korea.
authors.forename: M W
authors.initials: MW
authors.lastname: Kim
authors.forename: S J
authors.initials: SJ
authors.lastname: Moon
authors.forename: J H
authors.initials: JH
authors.lastname: Jung
authors.forename: Jaejun
authors.initials: J
authors.lastname: Yu
authors.forename: Sachin
authors.initials: S
authors.lastname: Parashar
authors.forename: P
authors.initials: P
authors.lastname: Murugavel
authors.forename: J H
authors.initials: JH
authors.lastname: Lee
authors.forename: T W
authors.initials: TW
authors.lastname: Noh