title: Exchange interaction effects on the optical properties of LuMnO3.
abstract: We have measured the optical conductivity of single crystal LuMnO3 from 10 to 45000 cm(-1) at temperatures between 4 and 300 K. A symmetry allowed on-site Mn d-d transition near 1.7 eV is observed to blueshift ( approximately 0.1 eV) in the antiferromagnetic state due to Mn-Mn superexchange interactions. Similar anomalies are observed in the temperature dependence of the TO phonon frequencies which arise from spin-phonon interaction. We find that the known anomaly in the temperature dependence of the quasistatic dielectric constant epsilon(0) below T(N) approximately 90 K is overwhelmingly dominated by the phonon contributions.
authors.affiliation: Materials Research Science and Engineering Center, University of Maryland, College Park, Maryland 20742, USA.
authors.forename: A B
authors.initials: AB
authors.lastname: Souchkov
authors.forename: J R
authors.initials: JR
authors.lastname: Simpson
authors.forename: M
authors.initials: M
authors.lastname: Quijada
authors.forename: H
authors.initials: H
authors.lastname: Ishibashi
authors.forename: N
authors.initials: N
authors.lastname: Hur
authors.forename: J S
authors.initials: JS
authors.lastname: Ahn
authors.forename: S W
authors.initials: SW
authors.lastname: Cheong
authors.forename: A J
authors.initials: AJ
authors.lastname: Millis
authors.forename: H D
authors.initials: HD
authors.lastname: Drew