Nature Commun. 6, 6594 (2015)

Controlling the spontaneous polarization of ferroelectric materials is essential for nonvolatile ferroelectric random memory (FeRAM). However, the need for physical contact between electrodes and ferroelectric materials makes it difficult to integrate FeRAM into devices. Now, Fernando Rubio-Marcos and co-workers from Spain and France report how polarized light with a wavelength of 532 nm can induce the motion of ferroelectric domain walls of a BaTiO3 single crystal without any physical contact. With the aid of optical microscopy and confocal Raman microscopy, mappings of the domain structure were obtained at the surface and deeper within the sample. Two well-known types of domains were identified by their characteristic Raman peak and the team also found a new type of domain, which appears at the surface like a domain boundary. Surprisingly, the new domain was sensitive to the polarized light and pushed away other domains. The authors say that the findings could ultimately yield a non-contact read-out method in FeRAM devices or remote control of piezoelectric actuators.