"Ultrafast Photovoltaic Response in Ferroelectric Nanolayers"

Daranciang, Dan: Highland, Matthew J., Wen, Haidan, Young, Steve M., Brandt, Nathaniel C., Hwang, Harold Y., Vattilana, Michael, Nicoul, Matthieu, Quirin, Florian, Goodfellow, John, Qi, Tingting, Grinberg, Ilya, Fritz, David M., Cammarata, Marco, Zhu, Diling, Lemke, Henrik T., Walko, Donald A., Dufresne, Eric M., Li, Yuelin, Larsson, Jörgen, Reis, David A., Sokolowski-Tinten, Klaus, Nelson, Keith A., Rappe, Andrew M., Fuoss, Paul H., Stephenson, G. Brian, Lindenberg, Aaron M.; Physical Review Letters, 02/23/12.

Additional Authors: Highland, Matthew J., Wen, Haidan, Young, Steve M., Brandt, Nathaniel C., Hwang, Harold Y., Vattilana, Michael, Nicoul, Matthieu, Quirin, Florian, Goodfellow, John, Qi, Tingting, Grinberg, Ilya, Fritz, David M., Cammarata, Marco, Zhu, Diling, Lemke, Henrik T., Walko, Donald A., Dufresne, Eric M., Li, Yuelin, Larsson, Jörgen, Reis, David A., Sokolowski-Tinten, Klaus, Nelson, Keith A., Rappe, Andrew M., Fuoss, Paul H., Stephenson, G. Brian, Lindenberg, Aaron M.

Abstract:

We show that light drives large-amplitude structural changes in thin films of the prototypical ferroelectric PbTiO3 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.