title: Transient lattice contraction in the solid-to-plasma transition.
abstract: In condensed matter systems, strong optical excitations can induce phonon-driven processes that alter their mechanical properties. We report on a new phenomenon where a massive electronic excitation induces a collective change in the bond character that leads to transient lattice contraction. Single large van der Waals clusters were isochorically heated to a nanoplasma state with an intense 10-fs x-ray (pump) pulse. The structural evolution of the nanoplasma was probed with a second intense x-ray (probe) pulse, showing systematic contraction stemming from electron delocalization during the solid-to-plasma transition. These findings are relevant for any material in extreme conditions ranging from the time evolution of warm or hot dense matter to ultrafast imaging with intense x-ray pulses or, more generally, any situation that involves a condensed matter-to-plasma transition.
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.; Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.
authors.forename: Ken R
authors.initials: KR
authors.lastname: Ferguson
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Maximilian
authors.initials: M
authors.lastname: Bucher
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.; Institut für Optik und Atomare Physik, Technische Universität Berlin, 10623 Berlin, Germany.
authors.forename: Tais
authors.initials: T
authors.lastname: Gorkhover
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Sébastien
authors.initials: S
authors.lastname: Boutet
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Hironobu
authors.initials: H
authors.lastname: Fukuzawa
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Jason E
authors.identifier: 0000-0001-6811-6083
authors.initials: JE
authors.lastname: Koglin
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kumagai
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Alberto
authors.initials: A
authors.lastname: Lutman
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Agostino
authors.initials: A
authors.lastname: Marinelli
authors.affiliation: National Science Foundation BioXFEL Science and Technology Center, Buffalo, NY 14203, USA.
authors.forename: Marc
authors.identifier: 0000-0002-8641-3302
authors.initials: M
authors.lastname: Messerschmidt
authors.affiliation: Division of Physics and Astronomy, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Kiyonobu
authors.initials: K
authors.lastname: Nagaya
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Jim
authors.identifier: 0000-0002-3540-3462
authors.initials: J
authors.lastname: Turner
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Ueda
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Garth J
authors.initials: GJ
authors.lastname: Williams
authors.affiliation: Department of Applied Physics, Stanford University, Stanford, CA 94305, USA.; Pulse Institute, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Philip H
authors.initials: PH
authors.lastname: Bucksbaum
authors.affiliation: Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.; Pulse Institute, Stanford University and SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.; Argonne National Laboratory, Lemont, IL 60439, USA.; Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208, USA.
authors.forename: Christoph
authors.initials: C
authors.lastname: Bostedt
mesh_terms: D008962:Models, Theoretical
keywords: cluster; scattering; ultrafast; x-ray