Bulk SrTi O3 is cubic and not expected to exhibit any first-order Raman scattering. However, nanocubes of SrTi O3 with an edge length of 80Â±10 nm show strong first-order Raman scattering originating from the breaking of symmetry caused by frozen surface dipoles (local tetragonality) and the presence of nanoscopic polar domains (arising from incorporated impurities). Rapid polarization fluctuations within these nanoscopic ferroelectric regions interfere with a polar phonon, resulting in a Fano-like asymmetric line shape in these SrTi O3 nanocubes, as well as in Ca0.3 Sr0.7 Ti O3 nanocubes.
Banerjee, Sarbajit; In Kim, Dae; Robinson, Richard D.; Herman, Irving P.; Mao, Yuanbing; and Wong, Stanislaus S., "Observation of Fano Asymmetry in Raman Spectra of SrTiO3 and Cax Sr1-xTiO3 Perovskite Nanocubes" (2006). Chemistry Faculty Publications and Presentations. 9.
Applied Physics Letters