Optical properties of quasi-tetragonal BiFeO3 thin films

Authors

P. Chen, University of TennesseeFollow
N. J. Podraza, Pennsylvania State University
X. S. Xu, University of Nebraska-LincolnFollow
A. Melville, Cornell University
E. Vlahos, Pennsylvania State University
V. Gopalan, Pennsylvania State University
R. Ramesh, University of California-Berkeley
D. G. Schlom, Cornell University
J. L. Musfeldt, University of Tennessee

Date of this Version

2010

Document Type

Article

Citation

Appl. Phys. Lett. 96, 131907 (2010)

Comments

Used by permission.

Abstract

Optical transmission spectroscopy and spectroscopic ellipsometry were used to extract the optical properties of an epitaxially grown quasi-tetragonal BiFeO₃ thin film in the near infrared to near ultraviolet range. The absorption spectrum is overall blue shifted compared with that of rhombohedral BiFeO₃, with an absorption onset near 2.25 eV, a direct 3.1 eV band gap, and charge transfer excitations that are ~0.4 eV higher than those of the rhombohedral counterpart. We interpret these results in terms of structural strain and local symmetry breaking.