Ghosez, Philippe[Maglione, Mario, ICMCB, UMR 5026, 87 Ave Docteur Schweitzer, F-33608 Pessac, France. Amoroso, Danila, Univ G DAnnunzio, Natl Res Council CNR SPIN, I-66100 Chieti, Italy. Veber, Philippe, Univ Claude Bernard Lyon 1, UMR 5306, ILM, Campus LyonTech La Doua,10 Rue Ada Byron, F-69622 Villeurbanne, France. Hatnean, Monica Ciomaga]
Kreisel, Jens[University of Luxembourg > Rectorate >]
Guennou, Mael[University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit]
ONE PHYSICS ELLIPSE, COLLEGE PK, MD 20740-3844 USA
[en] BaZrO3 is a perovskite that remains in the simple cubic phase at all temperatures, hence with no first-order Raman-active phonon mode allowed by symmetry. Yet, it exhibits an intense Raman spectrum with sharp and well-defined features. Here, we report the evolution of the Raman spectrum of BaZrO3 single crystals in a broad temperature range (4-1200 K) and discuss its origin with the support of detailed first-principle calculations of the lattice dynamics. Phonon calculations are performed not only for the cubic phase of BaZrO3, but also for the low-symmetry phases with octahedra tilts that have been suspected to exist at the nanoscale. We show that the Raman spectrum shows no direct evidence for these nanodomains, but can instead be explained by classical second-order Raman scattering. We provide an assignment of the dominant features to phonon mode combinations. In particular, we show that the high frequency range of the spectrum is dominated by overtones and shows an image of the phonon density of states corresponding to the stretching modes of the oxygen octahedra.
Luxembourg Institute of Science & Technology - LIST
[University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit]
