Micro-Raman spectroscopy has been used to study lattice dynamics associated with the ferroelectric domains of a BiFeO3 single crystal at low temperature. The phonon assignment shows a large frequency splitting between the transverse and longitudinal components of the A1 phonon mode related to the Bi-O bonds in contrast with thin films where the splitting is negligible. Applying an external electric field induces frequency shifts of the low energy modes related to the Bi-O bonds. These softenings are due to a tensile stress via the piezoelectric effect. We give estimates of the phonon deformation potentials.
@article{arxiv.0710.5412,
title = {Electric field effect on BiFeO$_3$ single crystal investigated by Raman spectroscopy},
author = {M. Cazayous and D. Malka and D. Lebeugle and D. Colson},
journal= {arXiv preprint arXiv:0710.5412},
year = {2009}
}