Photoinduced structural dynamics across metal-insulator transition in nickelate thin films

ORAL

Abstract

Rare earth nickelates display metal-insulator transition (MIT) which is accompanied by a magnetic transition, charge ordering, and a crystal structure change from orthorhombic to monoclinic. The size of the rare-earth cation affects the onset of MIT and the magnetic transition. Laser-induced excitation drives the transition at ultrafast timescales and can be used in combination with time resolved x-ray diffraction to disentangle the contribution of competing degrees of freedom. In this study, we focused on measuring the laser fluence dependent photoinduced structural response of epitaxial NdNiO3/ SrTiO3 (NNO/STO) and SmNiO3/SrTiO3 (SNO/STO) thin films. We utilized time-resolved x-ray diffraction to observe the evolution of the out of plane (002)pc Bragg peak and the in-plane (1-13)/2pc Bragg peak of NNO and SNO after laser excitation. The out of plane lattice parameter of NNO contracts for low fluences and expands for high fluences after laser excitation whereas an expansion in the SNO out of plane lattice parameter is observed for all fluences. The significantly faster structural recovery timescales of NNO compared to SNO indicate the role of the initial magnetic state on the photoinduced process.

*This work is supported by National Science Foundation (DMR-1902652)

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Publication: 'Photoinduced structural dynamics of nickelate thin films', Jugal Mehta, Scott Smith, Jianheng Li, Rahul Jangid, Kenneth Ainslie, Nadia Albayati, Pooja Rao, Yu-Hsing Cheng, Spencer Jeppson, Toyanath Joshi, Euvgenia Karapetrova, Donald A. Walko, Haidan Wen, David Lederman, and Roopali Kukreja, To be submitted, 2022.

Presenters

  • Jugal Mehta

    • University of California, Davis

Authors

  • Jugal Mehta

    • University of California, Davis

  • Scott Smith

    • University of California, Davis

  • Jianheng Li

    • University of California, Davis

  • Rahul Jangid

    • University of California, Davis

  • Kenneth Ainslie

    • University of California, Davis

  • Nadia Albayati

    • University of California, Davis

  • Pooja Rao

    • University of California, Davis

  • Yu Hsing Cheng

    • University of California, Davis

  • Spencer Jeppson

    • sdjeppson@ucdavis.edu
    • University of California, Davis

  • Donald A Walko

    • Argonne National Laboratory

  • Haidan Wen

    • Argonne National Laboratory

  • David Lederman

    • University of California, Santa Cruz

  • Roopali Kukreja

    • University of California, Davis