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A time-dependent order parameter for ultrafast photoinduced phase transitions


Strongly correlated electron systems often exhibit very strong interactions between structural and electronic degrees of freedom that lead to complex and interesting phase diagrams1,2. For technological applications of these materials it is important to learn how to drive transitions from one phase to another. A key question here is the ultimate speed of such phase transitions, and to understand how a phase transition evolves in the time domain3,4,5,6,7,8,9,10,11,12,13. Here we apply time-resolved X-ray diffraction to directly measure the changes in long-range order during ultrafast melting of the charge and orbitally ordered phase in a perovskite manganite. We find that although the actual change in crystal symmetry associated with this transition occurs over different timescales characteristic of the many electronic and vibrational coordinates of the system, the dynamics of the phase transformation can be well described using a single time-dependent ‘order parameter’ that depends exclusively on the electronic excitation.

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Figure 1: Ultrafast melting of charge and orbital order.
Figure 2: Measured (top) and simulated (bottom) evolution of the normalized diffracted X-ray intensity for three superlattice reflections.
Figure 3: Fluence dependence of charge order dynamics.
Figure 4: Optical phonon modes related to the charge and orbital order phase.


  1. Dagotto, E. Correlated electrons in high temperature superconductors. Rev. Mod. Phys. 66, 763–840 (1994).

    CAS  Article  Google Scholar 

  2. Imada, M., Fujimori, A. & Tokura, Y. Metal–insulator transitions. Rev. Mod. Phys. 70, 1039–1263 (1998).

    CAS  Article  Google Scholar 

  3. Cavalleri, A. et al. Femtosecond structural dynamics in VO2 during an ultrafast solid-solid phase transition. Phys. Rev. Lett. 87, 237401 (2001).

    CAS  Article  Google Scholar 

  4. Polli, D. et al. Coherent orbital waves in the photo-induced insulator-metal dynamics of a magnetoresistive manganite. Nature Mater. 6, 643–647 (2007).

    CAS  Article  Google Scholar 

  5. Schmitt, F. et al. Transient electronic structure and melting of a charge density wave in TbTe3 . Science 321, 1649–1652 (2008).

    CAS  Article  Google Scholar 

  6. Beaud, P. et al. An ultrafast structural phase transition driven by photo-induced melting of charge and orbital order. Phys. Rev. Lett. 103, 155702 (2009).

    CAS  Article  Google Scholar 

  7. Yusupov, R. et al. Coherent dynamics of macroscopic electronic order through a symmetry breaking transition. Nature Phys. 6, 681–684 (2010).

    CAS  Article  Google Scholar 

  8. Eichberger, M. et al. Snapshots of cooperative atomic motions in the optical suppression of charge density waves. Nature 468, 799–802 (2010).

    CAS  Article  Google Scholar 

  9. Rohwer, T. et al. Collapse of long-range charge order tracked by time-resolved photoemission at high momenta. Nature 471, 490–493 (2011).

    CAS  Article  Google Scholar 

  10. Först, M. et al. Driving magnetic order in a manganite by ultrafast lattice excitation. Phys. Rev. B 84, 241104(R) (2011).

    Article  Google Scholar 

  11. Johnson, S. L. et al. Femtosecond dynamics of the collinear-to-spiral antiferromagnetic phase transition in CuO. Phys. Rev. Lett. 108, 037203 (2012).

    CAS  Article  Google Scholar 

  12. Wall, S. et al. Ultrafast changes in lattice symmetry probed by coherent phonons. Nature Commun. 3, 721 (2012).

    CAS  Article  Google Scholar 

  13. De Jong, S. et al. Speed limit of the insulator–metal transition in magnetite. Nature Mater. 12, 882–886 (2013).

    CAS  Article  Google Scholar 

  14. Landau, L. D. & Lifschitz, E. M. Statistische Physik (Akademie-Verlag, 1987).

    Google Scholar 

  15. Tokura, Y. & Nagaosa, N. Orbital physics in transition-metal oxides. Science 288, 462–468 (2000).

    CAS  Article  Google Scholar 

  16. Singla, R. et al. Photoinduced melting of the orbital order in La0.5Sr1.5MnO4 measured with 4-fs laser pulses. Phys. Rev. B 88, 075107 (2013).

    Article  Google Scholar 

  17. Caviezel, A. et al. Identifying coherent lattice modulations coupled to charge and orbital order in a manganite. Phys. Rev. B 87, 205104 (2013).

    Article  Google Scholar 

  18. Zimmermann, M. V. et al. Interplay between charge, orbital, and magnetic order in Pr1 − xCaxMnO3 . Phys. Rev. Lett. 83, 4872–4875 (1999).

    Article  Google Scholar 

  19. Emma, P. et al. First lasing and operation of an ångstrom-wavelength free-electron laser. Nature Photon. 4, 641–647 (2010).

    CAS  Article  Google Scholar 

  20. Jung, J. H. et al. Midgap states of La1 − xCaxMnO3: Doping-dependent optical-conductivity studies. Phys. Rev. B 57, R11043 (1998).

    CAS  Article  Google Scholar 

  21. Matsuzaki, H. et al. Detecting charge and lattice dynamics in photoinduced charge-order melting in perovskite-type manganites using a 30-femtosecond time resolution. Phys. Rev. B 79, 235131 (2009).

    Article  Google Scholar 

  22. Okuyama, D. et al. Epitaxial-strain effect on charge/orbital order in Pr0.5Ca0.5MnO3 films. Appl. Phys. Lett. 95, 152502 (2009).

    Article  Google Scholar 

  23. Smolyaninova, V. N. et al. Anomalous field-dependent specific heat in charge-ordered Pr1 − xCaxMnO3 and La0.5Ca0.5MnO3 . Phys. Rev. B 62, 6093–6096 (2000).

    Article  Google Scholar 

  24. Ichikawa, H. et al. Transient photoinduced ‘hidden’ phase in a manganite. Nature Mater. 10, 101–105 (2011).

    CAS  Article  Google Scholar 

  25. Wadati, H. et al. Revealing orbital and magnetic phase transitions in Pr0.5Ca0.5MnO3 epitaxial thin films by resonant soft x-ray scattering. New J. Phys. 16, 033006 (2014).

    Article  Google Scholar 

  26. Van Veenendaal, M. Ultrafast photoinduced insulator-to-metal transitions in vanadium dioxide. Phys. Rev. B 87, 235118 (2013).

    Article  Google Scholar 

  27. Johnson, S. L. et al. Nanoscale depth-resolved coherent femtosecond motion in laser excited bismuth. Phys. Rev. Lett. 100, 155501 (2008).

    CAS  Article  Google Scholar 

  28. Harmand, M. et al. Achieving few-femtosecond time-sorting at hard X-ray free-electron lasers. Nature Photon. 7, 215–218 (2013).

    CAS  Article  Google Scholar 

  29. Herrmann, S. et al. CSPAD-140k: A versatile detector for LCLS experiments. Nucl. Instrum. Methods A 718, 550–553 (2013).

    CAS  Article  Google Scholar 

  30. Rodriguez, E. E., Proffen, Th., Llobet, A., Rhyne, J. J. & Mitchell, J. F. Neutron diffraction study of average and local structure in La0.5Ca0.5MnO3 . Phys. Rev. B 71, 104430 (2005).

    Article  Google Scholar 

  31. Amelitchev, V. A. et al. Structural and chemical analysis of colossal magnetoresistance manganites by Raman spectrometry. Phys. Rev. B 63, 104430 (2001).

    Article  Google Scholar 

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This work was supported by the NCCR Molecular Ultrafast Science and Technology (NCCR MUST), a research instrument of the Swiss National Science Foundation (SNSF). A.C. and T.K. acknowledge financial support by SNSF, Grants No. 200021_124496 and 200021_144115, respectively. Portions of this research were carried out at the Linac Coherent Light Source (LCLS) at SLAC National Accelerator Laboratory. LCLS is an Office of Science User Facility operated for the US Department of Energy Office of Science by Stanford University. Portions of this research received grants from the Japan Society for the Promotion of Science (JSPS) through the ‘Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program)’, initiated by the Council for Science and Technology Policy (CSTP). This work was partially supported by the Ministry of Education, Culture, Sports, Science and Technology of Japan (X-ray Free Electron Laser Priority Strategy Program).

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U.S., S.L.J. and P.B. conceived the experiment; A.C., S.O.M., S-W.H., C.D., H.W., H.T.L., M.C., G.I., T.H., J.A.J., A.F., T.K., M.R., S.L.J., U.S. and P.B. carried out the experiment; H.T.L., M.C., D.Z., J.M.G., M.S. and A.R. set up and operated the beamline including the optical pump laser; A.C., S.O.M., J.A.J., C.D., T.H. and H.T.L. analysed the data online during the experiments; A.C. analysed the data; H.W., M.N., M.K. and Y.T. conceived, designed and characterized the sample; S.O.M., L.R., A.C. and U.S. performed the static diffraction experiments; P.B. developed the model and performed the simulations with input from S.L.J.; P.B., S.L.J. and U.S. wrote the manuscript with discussions and improvements from all authors.

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Correspondence to P. Beaud.

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Beaud, P., Caviezel, A., Mariager, S. et al. A time-dependent order parameter for ultrafast photoinduced phase transitions. Nature Mater 13, 923–927 (2014).

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