Infrared phonon modes in multiferroic single-crystal FeTe2O5Br

Authors

K. H. Miller, University of Florida
X. S. Xu, University of Nebraska-LincolnFollow
H. Berger, Ecole Polytechnique Federale de Lausanne
V. Cracium, National Institute for Lasers, Plasma, and Radiation Physics
Xiaoxiang Xi, University of Florida
C. Martin, University of Florida
G. L. Carr, Brookhaven National Laboratory
D. B. Tanner, University of Florida

Date of this Version

2013

Document Type

Article

Citation

PHYSICAL REVIEW B 87, 224108 (2013)

Comments

Used by permission.

Abstract

Reflection and transmission as a function of temperature (7–300 K and 5–300 K respectively) have been measured on single crystals of the multiferroic compound FeTe₂O₅Br utilizing light spanning from the far infrared to the visible. The complex dielectric function and other optical properties were obtained via Kramers-Kronig analysis and by fits to a Drude-Lortentz model. Analysis of the anisotropic excitation spectra via Drude-Lorentz fitting and lattice dynamical calculations have led to the observation of 43 of the 53 modes predicted along the b axis of the monoclinic cell. The phonon response parallel to the a and c axes are also presented. Assignments to groups (clusters) of phonons have been made and trends within them are discussed in light of our calculated displacement patterns.