Direct imaging of ultrafast lattice dynamics

S Brennan Brown; A E Gleason; E Galtier; A Higginbotham; B Arnold; A Fry; E Granados; A Hashim; C G Schroer; A Schropp; F Seiboth; F Tavella; Z Xing; W Mao; H J Lee; B Nagler

doi:10.1126/sciadv.aau8044

Direct imaging of ultrafast lattice dynamics

Sci Adv. 2019 Mar 8;5(3):eaau8044. doi: 10.1126/sciadv.aau8044. eCollection 2019 Mar.

Authors

S Brennan Brown¹, A E Gleason^{2

3}, E Galtier⁴, A Higginbotham⁵, B Arnold⁴, A Fry⁴, E Granados⁴, A Hashim⁶, C G Schroer^{7

8}, A Schropp⁷, F Seiboth^{4

7}, F Tavella⁴, Z Xing⁴, W Mao^{3

9}, H J Lee⁴, B Nagler⁴

Affiliations

¹ Department of Mechanical Engineering, Stanford University, Building 530, 440 Escondido Mall, Stanford, CA 94305, USA.
² Shock and Detonation Physics, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545, USA.
³ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA.
⁴ Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Rd., Menlo Park, CA 94025, USA.
⁵ York Plasma Institute, Department of Physics, University of York, Heslington, YO10 5DD, UK.
⁶ Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA.
⁷ Photon Science, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, D-22607 Hamburg, Germany.
⁸ Department Physik, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.
⁹ Department of Geological Sciences, Stanford University, 367 Panama St., Stanford, CA 94305-2220, USA.

Abstract

Under rapid high-temperature, high-pressure loading, lattices exhibit complex elastic-inelastic responses. The dynamics of these responses are challenging to measure experimentally because of high sample density and extremely small relevant spatial and temporal scales. Here, we use an x-ray free-electron laser providing simultaneous in situ direct imaging and x-ray diffraction to spatially resolve lattice dynamics of silicon under high-strain rate conditions. We present the first imaging of a new intermediate elastic feature modulating compression along the axis of applied stress, and we identify the structure, compression, and density behind each observed wave. The ultrafast probe x-rays enabled time-resolved characterization of the intermediate elastic feature, which is leveraged to constrain kinetic inhibition of the phase transformation between 2 and 4 ns. These results not only address long-standing questions about the response of silicon under extreme environments but also demonstrate the potential for ultrafast direct measurements to illuminate new lattice dynamics.