@article{61b12b45c9564c308ae62760b366ac6d,
title = "Phase fluctuations and the absence of topological defects in a photo-excited charge-ordered nickelate",
abstract = "The dynamics of an order parameter's amplitude and phase determines the collective behaviour of novel states emerging in complex materials. Time- and momentum-resolved pump-probe spectroscopy, by virtue of measuring material properties at atomic and electronic time scales out of equilibrium, can decouple entangled degrees of freedom by visualizing their corresponding dynamics in the time domain. Here we combine time-resolved femotosecond optical and resonant X-ray diffraction measurements on charge ordered La 1.75 Sr 0.25 NiO 4 to reveal unforeseen photoinduced phase fluctuations of the charge order parameter. Such fluctuations preserve long-range order without creating topological defects, distinct from thermal phase fluctuations near the critical temperature in equilibrium. Importantly, relaxation of the phase fluctuations is found to be an order of magnitude slower than that of the order parameter's amplitude fluctuations, and thus limits charge order recovery. This new aspect of phase fluctuations provides a more holistic view of the phase's importance in ordering phenomena of quantum matter.",
author = "Lee, {W. S.} and Chuang, {Y. D.} and Moore, {R. G.} and Y. Zhu and L. Patthey and M. Trigo and Lu, {D. H.} and Kirchmann, {P. S.} and O. Krupin and M. Yi and M. Langner and N. Huse and Robinson, {J. S.} and Y. Chen and Zhou, {S. Y.} and G. Coslovich and B. Huber and Reis, {D. A.} and Kaindl, {R. A.} and Schoenlein, {R. W.} and D. Doering and P. Denes and Schlotter, {W. F.} and Turner, {J. J.} and Johnson, {S. L.} and M. F{\"o}rst and T. Sasagawa and Kung, {Y. F.} and Sorini, {A. P.} and Kemper, {A. F.} and B. Moritz and Devereaux, {T. P.} and Lee, {D. H.} and Shen, {Z. X.} and Z. Hussain",
note = "Funding Information: This research was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under Contract No. DE-AC02-76SF00515, SLAC National Accelerator Laboratory (SLAC), Stanford Institute for Materials and Energy Sciences (W.S.L., R.G.M., L.P., M.T, Y.C., D.A.R, Y.F.K., A.P.S., A.F.K., B.M, T.P.D., Z.X.S), SLAC Stanford Synchrotron Radiation Lightsource (D.H.Lu), SLAC Stanford PULSE Institute (M.T., D.A.R.) and under contract number DE-AC02-05CH11231 Lawrence Berkeley National Laboratory (LBNL) Advanced Light Source (Y.D.C., Z.H.), LBNL Materials Sciences Division (M.L., J.S.R., Y.Z., S.Y.Z., G.C., B.H. R.A.K., R.W.S.), LBNL Chemical Science Division (N. H.), and LBNL Engineering Division (D.D., P.D.). P.S.K acknowledges support by the Alexander-von-Humboldt Foundation through a Feodor-Lynen scholarship. Y.F.K. was supported by the Department of Defense (DoD) through the National Defense Science and Engineering Graduate Fellowship (NDSEG) Program. D.H.Lee acknowledges the support by the DOE grant number DE-AC02-05CH11231. The SXR Instrument at LCLS is funded by a consortium whose membership includes LCLS, Stanford University - SIMES, LBNL, University of Hamburg through the BMBF priority program FSP 301 and the Center for Free Electron Laser Science (CFEL).",
year = "2012",
doi = "10.1038/ncomms1837",
language = "English (US)",
volume = "3",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
}