Inelastic light scattering in incommensurate (IC) Ba2NaNb 5O15 reveals a dynamic central mode whose width satisfies tau -1(q,T)=D(T)q2 with diffusivity D(T) exhibiting a maximum of 0.85 cm2 s-1 at TR approximately=565 K, the temperature at which electron microscopy shows an abrupt roughening transition within the antiphase boundaries (APBs). This phase change involves a transition from modulation along one axis (1q) to modulation along two orthogonal axes (2q). The dynamic central mode is also observed to couple strongly with the (100) longitudinal acoustic (LA) phonon.
ASJC Scopus subject areas
- Condensed Matter Physics
- Electronic, Optical and Magnetic Materials