title: Visualization of nanocrystal breathing modes at extreme strains.
abstract: Nanoscale dimensions in materials lead to unique electronic and structural properties with applications ranging from site-specific drug delivery to anodes for lithium-ion batteries. These functional properties often involve large-amplitude strains and structural modifications, and thus require an understanding of the dynamics of these processes. Here we use femtosecond X-ray scattering techniques to visualize, in real time and with atomic-scale resolution, light-induced anisotropic strains in nanocrystal spheres and rods. Strains at the percent level are observed in CdS and CdSe samples, associated with a rapid expansion followed by contraction along the nanosphere or nanorod radial direction driven by a transient carrier-induced stress. These morphological changes occur simultaneously with the first steps in the melting transition on hundreds of femtosecond timescales. This work represents the first direct real-time probe of the dynamics of these large-amplitude strains and shape changes in few-nanometre-scale particles.
authors.affiliation: 1] Department of Chemistry, Stanford University, Stanford, California 94305, USA [2] Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Erzsi
authors.initials: E
authors.lastname: Szilagyi
authors.affiliation: Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: Joshua S
authors.initials: JS
authors.lastname: Wittenberg
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Miller
authors.affiliation: Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA.
authors.forename: Katie
authors.initials: K
authors.lastname: Lutker
authors.affiliation: Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Quirin
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Henrik
authors.initials: H
authors.lastname: Lemke
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Diling
authors.initials: D
authors.lastname: Zhu
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Chollet
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Robinson
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Haidan
authors.initials: H
authors.lastname: Wen
authors.affiliation: Faculty of Physics and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Lotharstrasse 1, 47048 Duisburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Sokolowski-Tinten
authors.affiliation: 1] Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA [2] Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA [3] Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Lindenberg