Speaker
Dr
Paul Beaud
(Paul Scherrer Institut)
Description
The exploration of the subtle interaction of structural and electronic degrees of freedom in strongly correlated electron systems on the femtosecond time scale is an emerging area of research. One goal of these studies is to advance our understanding of the underlying correlations, another is to find ways to control on an ultrafast time scale the technological relevant properties of these materials. Perovskite manganites, prototypical examples of strongly correlated materials, exhibit properties such as colossal magnetoresistance and insulator-to-metal transitions that are intrinsically related to symmetry changes of the atomic lattice and to fascinating ordering patterns of the spins, charges and orbitals. Here we report on a recent study on the dynamics of photoexcited epitaxial film of Pr0.5Ca0.5MnO3 using femtosecond resonant x-ray diffraction. Taking advantage of the high flux of the LCLS free electron laser we are able to access different classes of superlattice reflections, each with sensitivity to different components of the phase transition. We find that although the actual change in crystal symmetry associated with this transition occurs over different time scales characteristic of the many electronic and vibrational coordinates of the system [1-3], the dynamics of the phase transformation can be well described using a single time-dependent ‘order parameter’ that depends exclusively on the electronic excitation.
Primary author
Dr
Paul Beaud
(Paul Scherrer Institut)
Co-authors
Dr
Andres Ferrer
(Institute of Quantum Electronics, ETH Zürich)
Dr
Andrin Caviezel
(Paul Scherrer Institut)
Dr
Christian Dornes
(Institute of Quantum Electronics, ETH Zurich)
Dr
Dilling Zhu
(LCLS, SLAC National Accelerator Laboratory, Menlo Park, California, USA)
Dr
Gerhard Ingold
(Paul Scherrer Institut)
Dr
Henrik Lemke
(LCLS, SLAC National Accelerator Laboratory, Menlo Park, California, USA)
Dr
Hiroki Wadati
(Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Tokyo 113-8656, Japan)
J. Glownia
(LCLS, SLAC National Accelerator Laboratory, Menlo Park, California, USA)
Dr
Jeremy Johnson
(Paul Scherrer Institut)
Dr
Laurenz Rettig
(Paul Scherrer Institut)
Prof.
M. Kawasaki
(Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Tokyo 113-8656, Japan)
Dr
Marcin Sikorski
(LCLS, SLAC National Accelerator Laboratory, Menlo Park, California, USA)
Dr
Mathieu Chollet
(LCLS, SLAC National Accelerator Laboratory, Menlo Park, California, USA)
Dr
Matsuo Nakamura
(RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan)
Dr
Milan Radovic
(Paul Scherrer Institut)
Dr
Robert Aymeric
(LCLS, SLAC National Accelerator Laboratory, Menlo Park, California, USA)
Dr
Shih-Wen Huang
(Paul Scherrer Institut)
Dr
Simon Mariager
(Paul Scherrer Institut)
Prof.
Steven Johnson
(Institute of Quantum Electronics, ETH Zurich)
Ms
Teresa Kubacka
(Institute of Quantum Electronics, ETH Zurich)
Mr
Tim Huber
(Institute of Quantum Electronics, ETH Zurich)
Dr
Urs Staub
(Paul Scherrer Institut)
Prof.
Y. Tokura
(Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo, Hongo, Tokyo 113-8656, Japan)
