title: Phase transition in single crystal Cs2Nb4O11.
abstract: We studied temperature dependence of complex capacitance, impedance, and polarized Raman spectra of single crystal Cs2Nb4O11. First, we observed a sharp lambda-shaped peak at 165 degrees C in the complex capacitance, then found drastic changes in the Raman spectra in the same temperature range. Utilizing the pseudosymmetry search of structure space group, we attributed the observed anomalies to a structural change from the room temperature orthorhombic Pnn2 to another orthorhombic Imm2. We also measured room temperature polarized Raman spectra in different symmetries of normal vibrations and assigned high wavenumber Raman bands to the internal vibrations of NbO6 octahedra and NbO4 tetrahedra.
authors.affiliation: Department of Physics, University of Nebraska, Omaha, Nebraska 68182-0266, USA. jliu@unlserve.unl.edu
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.forename: E P
authors.initials: EP
authors.lastname: Kharitonova
authors.forename: Chun-Gang
authors.initials: CG
authors.lastname: Duan
authors.forename: W N
authors.initials: WN
authors.lastname: Mei
authors.forename: R W
authors.initials: RW
authors.lastname: Smith
authors.forename: J R
authors.initials: JR
authors.lastname: Hardy