Giant optical enhancement of strain gradient in ferroelectric BiFeO3 thin films and its physical origin.

ABSTRACT: Through mapping of the spatiotemporal strain profile in ferroelectric BiFeO3 epitaxial thin films, we report an optically initiated dynamic enhancement of the strain gradient of 10(5)-10(6)?m(-1) that lasts up to a few ns depending on the film thickness. Correlating with transient optical absorption measurements, the enhancement of the strain gradient is attributed to a piezoelectric effect driven by a transient screening field mediated by excitons. These findings not only demonstrate a new possible way of controlling the flexoelectric effect, but also reveal the important role of exciton dynamics in photostriction and photovoltaic effects in ferroelectrics.

SUBMITTER: Li Y 

PROVIDER: S-EPMC4653733 | biostudies-literature | 2015 Nov

REPOSITORIES: biostudies-literature