Abstract
We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric via direct coupling to its intrinsic photovoltaic response. Using time-resolved x-ray scattering to visualize atomic displacements on femtosecond time scales, photoinduced changes in the unit-cell tetragonality are observed. These are driven by the motion of photogenerated free charges within the ferroelectric and can be simply explained by a model including both shift and screening currents, associated with the displacement of electrons first antiparallel to and then parallel to the ferroelectric polarization direction.
- Received 3 August 2011
DOI:https://doi.org/10.1103/PhysRevLett.108.087601
© 2012 American Physical Society