Dielectric Properties of Ferroelectric Domain Walls by Raman Spectroscopy

ABSTRACT A simple and nondestructive method for local characterization of the domain walls properties based on the confocal Raman microscopy and Lyddane−Sachs−Teller relation is proposed. The polarized Raman spectra were measured at polar and nonpolar surfaces of stoichiometric lithium niobate single crystal, and the variations of most high‐frequency spectral lines in the vicinity of 180° domain walls were revealed. The obtained results were then used in generalized Lyddane−Sachs−Teller relation to get insight on the dielectric property variations near the domain walls. The refractive index contrast corresponding to these variations is comparable with the results provided by optical coherence tomography. The new approach can help to improve the methods of domain wall engineering and facilitate the development of novel nanoelectronic and optoelectronic nanoelectronic devices.