Broken symmetry in low-temperature BaTiO3 phases: Strain effects probed by Raman scattering

Abstract

Micro-Raman spectroscopy is utilized to study the temperature dependence of domain structures in a high-quality BaTiO3 bulk crystal. For T=4–100 K, the spectra of the initially 90° domain wall region at room temperature exhibit the splitting of A1 mode at ∼244 cm−1 with the appearance of an additional peak at ∼263 cm−1, the behavior of which is different from that of a sharp peak observed at ∼244 cm−1 in the single-domain region. The results imply that the strain fields exist in the domain walls at low temperatures, thus altering the local crystal symmetry.