Year: 2014
Type: article
Abstract: Coherent phonons (CPs) generated by laser pulses on the femtosecond scale have been proposed as a means to achieve ultrafast, nonthermal switching in phase-change materials such as ${\mathrm{Ge}}_{2}{\mathrm{Sb}}_{2}{\mathrm{Te}}_{5}$ (GST). Here we use ultrafast optical pump pulses to induce coherent acoustic phonons and stroboscopically measure the corresponding lattice distortions in GST using 100-ps x-ray pulses from the European Synchrotron Radiation Facility (ESRF) storage ring. A linear-chain model provides a good description of the observed changes in the diffraction signal; however, the magnitudes of the measured shifts are too large to be explained by thermal effects alone, implying the presence of excited-state effects in addition to temperature-driven expansion. The information on the movement of atoms during the excitation process can lead to greater insight into the possibilities of using CP-induced phase transitions in GST.
Source: Physical Review B
Institutions: SPring-8, Japan Synchrotron Radiation Research Institute, National Institute of Advanced Industrial Science and Technology, Paul Drude Institute for Solid State Electronics, Helmholtz-Zentrum Berlin für Materialien und Energie, Deutsches Elektronen-Synchrotron DESY, Singapore University of Technology and Design, University of Tsukuba
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: bronze
Awards: G7410774597, G8817403034, G8841008179
OpenAlex ID: W2073869729