Picosecond strain dynamics in Ge2Sb2Te5monitored by time-resolved x-ray diffraction

Paul Fons, Peter Rodenbach, Kirill V. Mitrofanov, Alexander V. Kolobov, Junji Tominaga, Roman Shayduk, Alessandro Giussani, Raffaella Calarco, Michael Hanke, Henning Riechert, Robert E. Simpson, Muneaki Hase

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

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 Ge2Sb2Te5(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.

Original languageEnglish
Article number094305
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume90
Issue number9
DOIs
Publication statusPublished - 2014 Sep 25
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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