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Ultrafast Photovoltaic Response in Ferroelectric Nanolayers

2012; American Physical Society; Volume: 108; Issue: 8 Linguagem: Inglês

10.1103/physrevlett.108.087601

1092-0145

Dan Daranciang, Matthew J. Highland, Haidan Wen, Steve M. Young, Nathaniel C. Brandt, Harold Y. Hwang, Michael Vattilana, M. Nicoul, Florian Quirin, John Goodfellow, Tingting Qi, Ilya Grinberg, David Fritz, Marco Cammarata, Diling Zhu, H. Lemke, Donald A. Walko, Eric M. Đufresne, Yuelin Li, Jörgen Larsson, David A. Reis, K. Sokolowski-Tinten, Keith A. Nelson, Andrew M. Rappe, P. H. Fuoss, G. B. Stephenson, Aaron M. Lindenberg,

Multiferroics and related materials

We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric ${\mathrm{PbTiO}}_{3}$ 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.