TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Blome, Christian A1 - Blums, Juris A1 - Cavalleri, Andrea A1 - Dietrich, Clemens A1 - Tarasevitch, Alexander A1 - Uschmann, Ingo A1 - Förster, Eckhard A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - von der Linde, Dietrich T1 - Femtosecond X-ray measurement of coherent lattice vibrations near the Lindemann stability limit JF - Nature N2 - The study of phase-transition dynamics in solids beyond a time-averaged kinetic description requires direct measurement of the changes in the atomic configuration along the physical pathways leading to the new phase. The timescale of interest is in the range 10(-14) to 10(-12) s. Until recently, only optical techniques were capable of providing adequate time resolution, albeit with indirect sensitivity to structural arrangement. Ultrafast laser-induced changes of long-range order have recently been directly established for some materials using time-resolved X-ray diffraction. However, the measurement of the atomic displacements within the unit cell, as well as their relationship with the stability limit of a structural phase, has to date remained obscure. Here we report time-resolved X-ray diffraction measurements of the coherent atomic displacement of the lattice atoms in photoexcited bismuth close to a phase transition. Excitation of large-amplitude coherent optical phonons gives rise to a periodic modulation of the X-ray diffraction efficiency. Stronger excitation corresponding to atomic displacements exceeding 10 per cent of the nearest-neighbour distance-near the Lindemann limit-leads to a subsequent loss of long-range order, which is most probably due to melting of the material. Y1 - 2003 U6 - https://doi.org/10.1038/nature01490 VL - 422 IS - 6929 SP - 287 EP - 289 PB - Springer ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Leitner, D. M. A1 - Tóth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Kammler, Martin T1 - Transient lattice dynamics in fs-laser-excited semiconductors probed by ultrafast X-ray diffraction JF - Journal de Physique IV N2 - A study of lattice dynamics in fs-laser-excited crystalline bulk Ge and Ge/Si-heterostructures, using time-resolved x-ray diffraction, was presented. Fast energy transport deep into the bulk of the material, coherent acoustic phonon dynamics, lattice anharmonicity, and vibrational transport across a buried interfaces were observed. Graphs showing time-dependent shifts of the centroid of the measured rocking curves in the Ge-overlayer and in the Si-substrate for different fluences, were presented. Y1 - 2001 U6 - https://doi.org/10.1051/jp4:2001290 VL - 11 IS - Pr2 SP - 473 EP - 477 PB - EDP ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Leitner, D. M. A1 - Tóth, Csaba A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. T1 - Time-resolved x-ray diffraction study of ultrafast acoustic phonon dynamics in Ge/Si-heterostructures JF - Chemical Physics N2 - Using time-resolved x-ray diffraction the ultafast strain dynamics in fs-laserexcited Ge/Si-heterostructures has been studied. A fluence dependent, anharmonic damping of the impulsively generated acoustic phonons and vibrational transport across the buried Ge/Si-interface are observed. Y1 - 2001 U6 - https://doi.org/10.1007/978-3-642-56546-5_81 VL - 66 SP - 281 EP - 283 PB - Springer ER - TY - CHAP A1 - Sokolowski-Tinten, Klaus A1 - Blome, Christian A1 - Dietrich, Clemens A1 - Blums, Juris A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Cavalleri, Andrea A1 - Squier, Jeff A. A1 - Kammler, Martin T1 - Structural dynamics in laser-excited solids investigated with femtosecond x-ray diffraction T2 - 2002 Summaries of Papers Presented at the Quantum Electronics and Laser Science Conference, 19-24 May 2002, Long Beach, CA, USA N2 - Summary form only given. Ultrashort x-ray pulses offer a unique combination of atomic-scale spatial and temporal resolution, which permits direct measurements of structural transients on an ultrafast time scale. Using time-resolved X-ray diffraction with femtosecond, multi-keV X-ray pulses we have studied transient lattice dynamics in optically excited semiconductors. Y1 - 2002 U6 - https://doi.org/10.1109/QELS.2002.1031182 SP - 115 EP - 116 PB - IEEE ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Blome, Christian A1 - Dietrich, Clemens A1 - Tarasevitch, A. A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Cavalleri, Andrea A1 - Squier, Jeff A. A1 - Kammler, Martin T1 - Femtosecond x-ray measurement of ultrafast melting and large acoustic transients JF - Physical review letters N2 - Time-resolved x-ray diffraction with ultrashort ( approximately 300 fs), multi-keV x-ray pulses has been used to study the femtosecond laser-induced solid-to-liquid phase transition in a thin crystalline layer of germanium. Nonthermal melting is observed to take place within 300-500 fs. Following ultrafast melting we observe strong acoustic perturbations evolving on a picosecond time scale. Y1 - 2001 U6 - https://doi.org/10.1103/PhysRevLett.87.225701 VL - 87 PB - APS ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Blome, Christian A1 - Dietrich, Clemens A1 - Tarasevitch, A. A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Cavalleri, Andrea A1 - Squier, Jeff A. A1 - Kammler, Martin T1 - Femtosecond time-resolved X-ray diffraction study of ultrafast structural dynamics in laser-excited solids JF - International Conference on Ultrafast Phenomena, 12 May 2002, Vancouver Canada N2 - Time-resolved x-ray diffraction with sub-300 fs, multi-keV x-ray pulses was used to study ultrafast lattice dynamics in laser-irradiated germanium and bismuth. In bismuth strong excitation of optical phonons is observed prior to disordering of the material. Y1 - 2002 U6 - https://doi.org/10.1007/978-3-642-59319-2_10 VL - 71 SP - 36 EP - 38 PB - Optica Publishing Grou ER - TY - JOUR A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Leitner, D. M. A1 - Tóth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Sokolowski-Tinten, Klaus A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Kammler, Martin T1 - Anharmonic lattice dynamics in germanium measured with ultrafast x-ray diffraction JF - Physical review letters N2 - Damping of impulsively generated coherent acoustic oscillations in a femtosecond laser-heated thin germanium film is measured as a function of fluence by means of ultrafast x-ray diffraction. By simultaneously measuring picosecond strain dynamics in the film and in the unexcited silicon substrate, we separate anharmonic damping from acoustic transmission through the buried interface. The measured damping rate and its dependence on the calculated temperature of the thermal bath is consistent with estimated four-body, elastic dephasing times (T2) for 7-GHz longitudinal acoustic phonons in germanium. Y1 - 2000 U6 - https://doi.org/10.1103/PhysRevLett.85.586 VL - 85 IS - 3 SP - 586 EP - 589 PB - APS ER - TY - JOUR A1 - Sokolowski-Tinten, Klaus A1 - Horn-von Hoegen, Michael A1 - von der Linde, D. A1 - Cavalleri, Andrea A1 - Siders, C. W. A1 - Brown, F. L. H. A1 - Tóth, Csaba A1 - Squier, Jeff A. A1 - Barty, C. P. J. A1 - Wilson, K. R. A1 - Kammler, Martin T1 - Time-resolved x-ray diffraction study of ultrafast acoustic phonon dynamics in Ge/Si-heterostructures JF - International Conference on Ultrafast Phenomena , 9 July 2000, Charleston N2 - Using time-resolved x-ray diffraction the ultafast strain dynamics in fs-laserexcited Ge/Si-heterostructures has been studied. A fluence dependent, anharmonic damping of the impulsively generated acoustic phonons and vibrational transport across the buried Ge/Si-interface are observed. KW - Acoustic Phonon KW - Acoustic Transmission KW - Carrier Diffusion KW - Homogenous Expansion KW - Lattice Anharmonicity Y1 - 2000 UR - https://opg.optica.org/abstract.cfm?uri=UP-2000-MF43 PB - Optica ER - TY - JOUR A1 - Siders, C. W. A1 - Cavalleri, Andrea A1 - Sokolowski-Tinten, Klaus A1 - Tóth, Csaba A1 - Guo, T. A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - Wilson, K. R. A1 - von der Linde, D. A1 - Barty, C. P. J. T1 - Detection of nonthermal melting by ultrafast X-ray diffraction JF - Science N2 - Using ultrafast, time-resolved, 1.54 angstrom x-ray diffraction, thermal and ultrafast nonthermal melting of germanium, involving passage through nonequilibrium extreme states of matter, was observed. Such ultrafast, optical-pump, x-ray diffraction probe measurements provide a way to study many other transient processes in physics, chemistry, and biology, including direct observation of the atomic motion by which many solid-state processes and chemical and biochemical reactions take place. Y1 - 1999 U6 - https://doi.org/10.1126/science.286.5443.1340 VL - 286 IS - 5443 SP - 1340 EP - 1342 ER - TY - JOUR A1 - Siders, C. W. A1 - Cavalleri, Andrea A1 - Sokolowski-Tinten, Klaus A1 - Tóth, Csaba A1 - Guo, T. A1 - Kammler, Martin A1 - Horn-von Hoegen, Michael A1 - Wilson, K. R. A1 - von der Linde, D. A1 - Barty, C. P. J. T1 - Direct Observation of Ultrafast Non-thermal Melting by Ultrafast X-ray Diffraction JF - Ultrafast Phenomena XII N2 - Ultrafast nonthermal melting of femtosecond laser-irradiated germanium was observed directly for the first time using sub-picosecond, 1.54-angstrom x-ray diffraction. Such measurements allow the study of transient atomic motion fundamental to many processes in physics, chemistry, and biology. Y1 - 2000 U6 - https://doi.org/10.1007/978-3-642-56546-5_80 VL - 66 SP - 276 EP - 280 PB - Springer ER -