Seminario del Departamento de Física de la Materia Condensada: "X-ray Photon Correlation Spectroscopy Studies of Equilibrium and Non-Equilibrium Dynamics in Materials".- Jueves 12 de junio
El jueves 12 de junio de 2025 se celebrará un seminario organizado por el Departamento de Física de la Materia Condensada de la Universidad de Zaragoza, con Brian Stephenson, prestigioso físico del Argonne National Laboratory, que ofrecerá la conferencia titulada "X-ray Photon Correlation Spectroscopy Studies of Equilibrium and Non-Equilibrium Dynamics in Materials".
La sesión tendrá lugar a las 12:30 horas en la Sala de Grados de la Facultad de Ciencias de la Universidad de Zaragoza.
Brian es uno de los grandes expertos e impulsores de las técnicas de sincrotrón basadas en rayos X coherentes, y de hecho fue director de la Fuente sincrotrón Advanced Photon Source (Argonne). En este seminario nos hablará del uso de haces de rayos X coherentes para el estudio de las propiedades dinámicas en sistemas líquidos y durante el crecimiento de materiales cristalinos.
Resumen (en inglés):
The greatly increased brightness of synchrotron hard X-ray sources has enabled a new set of experimental methods using coherent X-ray beams. One of these, X-ray photon correlation spectroscopy (XPCS), is sensitive to structural dynamics on length scales down to the atomic scale. Using a coherent beam, one can resolve the speckle pattern in diffuse X-ray scattering from disordered structures. This speckle is sensitive to the exact arrangement of the disorder, not just its average properties. The time dependence of the speckle thus reveals dynamics and correlations not visible without a coherent beam. We will illustrate the technique with results from three recent studies of dynamics in materials: equilibrium critical fluctuations in a complex liquid [1], steady-state surface island nucleation during layer-by-layer cristal growth [2], and driven domain switching in a ferroelectric thin film. Continuing upgrades to synchrotron sources promise to make XPCS studies possible for an ever-widening range of materials processes.
Work supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Divisions of Materials Sciences and Engineering and Chemical Sciences, Geosciences, and Biosciences.
[1] D. Sheyfer, Q. Zhang, J. Lal, T. Loeffler, E. M. Dufresne, A. R. Sandy, S. Narayanan, S.K.R.S. Sankaranarayanan, R. Szczygiel, P. Maj, L. Soderholm, M. R. Antonio, and G. B. Stephenson, Physical Review Letters 125, 125504 (2020).
[2] G. Ju, D. Xu, M. J. Highland, C. Thompson, H. Zhou, J. A. Eastman, P. H. Fuoss, P. Zapol, H. Kim, and G. B. Stephenson, Nature Physics 15, 589 (2019).
