Nonequilibrium lattice dynamics measurements with ultrafast x-ray pulses

ORAL  · Invited

Abstract

There is growing interest in the use of ultrafast light pulses to drive nonequilibrium states of materials with novel properties. Our understanding of how to generate and control these states requires time-resolved atomic-scale probes of structure and dynamics. In this talk, we report results of femtosecond x-ray free-electron laser-based scattering experiments which help elucidate the excited-state dynamics of photo-excited materials. In the case of SnSe, we find that above-gap photoexcitation drives the material towards a higher-symmetry structure that does not exist thermal equilibrium. First principle calculations help us identify how photoexcitation from localized valence bands drives changes in the orbital hybridization leading to this instability. From the measured excited-state phonon dispersion we further identify changes in the interlayer bonding that are responsible for driving this novel instability, consistent with the changes in the orbital character of the bands. Our work suggest the importance of pump-wavelength for control of structural distortions through orbitally-selective above-gap excitation.

*This work was funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences through the Division of Materials Sciences and Engineering under Contract No. DE-AC02- 76SF00515

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Publication: M. Trigo, M. Fuchs, J. Chen, M. P. Jiang, M. Cammarata, S. Fahy, D. M. Fritz, K. Gaffney, S. Ghimire, A. Higginbotham, S. L. Johnson, M. E. Kozina, J. Larsson, H. Lemke, A. M. Lindenberg, G. Ndabashimiye, F. Quirin, K. Sokolowski-Tinten, C. Uher, G. Wang, J. S. Wark, D. Zhu, and D. A. Reis. Fourier-transform inelastic x-ray scattering from time- and momentum-dependent phonon–phonon correlations. Nature Physics, 9(12):790–794, 2013.

S. W. Teitelbaum, T. Henighan, Y. Huang, H. Liu, M. P. Jiang, D. Zhu, M. Chollet, T. Sato, E. D. Murray, S. Fahy, S. O'Mahony, T. P. Bailey, C. Uher, M. Trigo, and D. A. Reis. Direct measurement of anharmonic decay channels of a coherent phonon. Phys. Rev. Lett., 121:125901, 2018.

S. W. Teitelbaum, T. C. Henighan, H. Liu, M. P. Jiang, D. Zhu, M. Chollet, T. Sato, E. D. Murray, S. Fahy, S. O'Mahony, T. P. Bailey, C. Uher, M. Trigo, and D. A. Reis. Measurements of nonequilibrium interatomic forces using time-domain x-ray scattering. Phys. Rev. B, 103:L180101, 2021.

Y. Huang, S. Yang, S. Teitelbaum, G. de la Peña, T. Sato, M. Chollet, D. Zhu, J. L. Niedziela, D. Bansal, A. F. May, A. M. Lindenberg, O. Delaire, D. A. Reis, and M. Trigo. Observation of a novel lattice instability in ultrafast photoexcited SnSe. Phys. Rev. X, 12:011029, 2022.

Y. Huang, S. Yang, G. de la Peña, T. Sato, M. Chollet, D. Zhu, J. L. Niedziela, D. Bansal, A. F. May, A. M. Lindenberg, O. Delaire, D. A. Reis, and M. Trigo, Novel Lattice Instability in SnSe with a Nonthermal Bonding Origin, in preperation.

Presenters

  • David A Reis

    • Stanford Univ
    • Stanford PULSE Institute

Authors

  • David A Reis

    • Stanford Univ
    • Stanford PULSE Institute

  • Yijing Huang

    • Stanford University
    • Stanford Univ

  • Mariano Trigo

    • SLAC - Natl Accelerator Lab

  • Shan Yang

    • Duke University

  • Olivier Delaire

    • Duke University

  • Samuel W Teitelbaum

    • Arizona State University
    • ASU

  • Andrew F May

    • Oak Ridge National Lab
    • Oak Ridge National Laboratory

  • Aaron M Lindenberg

    • Stanford Univ

  • Diling Zhu

    • SLAC - Natl Accelerator Lab

  • Takahiro Sato

    • SLAC National Accelerator Laboratory
    • SLAC - Natl Accelerator Lab
    • SLAC

  • Matthieu Chollet

    • slac
    • SLAC National Accelerator Laboratory

  • Jennifer Niedziela

    • Oak Ridge National Lab

  • Dipanshu Bansal

    • Indian Inst of Tech-Bombay

  • Gilberto De La Pena

    • SLAC - Natl Accelerator Lab
    • University of Illinois at Urbana-Champaign