Ultrafast resonant X-ray scattering investigation of non-thermal melting using XFELs

ORAL

Abstract

Ultrafast melting transitions in noble metals and semiconductors irradiated by femtosecond IR laser have been reported with signatures of lattice disorder in less than a picosecond timescale, which is faster than electron-phonon energy transfer rates. With this mysteriously fast reaction of crystal lattice, the interest in unveiling the fundamental energy transfer mechanism has been intense with extensive research effort using ultrafast electron diffraction, time resolved X-ray diffraction, etc. By employing time-resolved resonant X-ray scattering, we have investigated the ultrafast lattice melting with femtosecond IR laser irradiation synchronized to the X-ray laser pulses from PAL-XFEL. Experimental evidence on the electron transition driven lattice disorder has been obtained, supporting the bond softening explanation on the nonthermal melting in covalent bonding crystals. IR laser fluence dependence of the melting time suggests essential role of electrons in bonding orbitals in causing the crystal melting.

*This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education (2016R1A6B2A02005471).

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Presenters

  • Heemin Lee

    • Pohang University of Science and Technology
    • Department of Physics, Pohang University of Science and Technology

Authors

  • Heemin Lee

    • Pohang University of Science and Technology
    • Department of Physics, Pohang University of Science and Technology

  • Do Hyung Cho

    • Pohang University of Science and Technology
    • Department of Physics, Pohang University of Science and Technology

  • Daeho Sung

    • Pohang University of Science and Technology
    • Department of Physics, Pohang University of Science and Technology

  • Chulho Jung

    • Pohang University of Science and Technology
    • Department of Physics, Pohang University of Science and Technology

  • Seonghyun Han

    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology

  • Sung Soo Ha

    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology
    • Gwangju Institute of Science and Technology

  • Muhammad Ijaz Anwar

    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology

  • Daewoong Nam

    • Pohang Accelerator Laboratory
    • Pohang Accelerator Lab (PAL)

  • Byeong-Gwan Cho

    • Pohang Accelerator Lab (PAL)

  • Sunam Kim

    • Pohang Accelerator Lab (PAL)
    • Pohang Accelerator Laboratory,, Pohang Accelerator Laboratory,

  • Jaegu Park

    • Pohang Accelerator Lab (PAL)

  • In Tae Eom

    • Pohang Accelerator Lab (PAL)

  • Sehwan Cheon

    • Pohang Accelerator Lab (PAL)
    • Pohang Accelerator Laboratory,, Pohang Accelerator Laboratory,

  • Tae-Yeong Koo

    • Pohang Accelerator Lab (PAL)

  • Do Young Noh

    • Dept. of Physics and Photon Science, GIST
    • Department of Physics and Photon Science, Gwangju Institute of Science and Technology
    • Gwangju Institute of Science and Technology

  • Changyong Song

    • Pohang University of Science and Technology
    • Department of Physics, Pohang University of Science and Technology