Symmetry Breaking in a Polar Metal Probed with XUV Second Harmonic Generation

POSTER

Abstract

It was first predicted over 50 years ago that polar metals could form through a 2nd order phase transition, but the first experimentally realized polar metal, LiOsO3, was discovered only recently [1]. In LiOsO3, a continuous phase transition occurs at Tc = 140 K, where it transitions from a nonpolar metallic to a polar metallic phase through the loss of inversion symmetry. Previous measurements have shown that the transition involves a coordinated 0.5 Å displacement of Li-ions along the polar axis. To gain insight into the nature of the Li-coordination environment in the polar phase, we turn to extreme ultraviolet second harmonic generation (XUV-SHG) at a free electron laser (XFEL). Here, we directly probe the dielectric environment around the Li-ion below Tc by tuning the incident XFEL energy to be half-resonant with energies around the Li K-edge [2]. We extract the effective X(2) and use ab initio simulations to relate the nonlinear response to the Li coordination environment. Our results provide insight into the Li-bonding environment and pave the way for future ultrafast time-resolved studies of phase transitions involving structural distortions.

[1] Y. Shi et al., Nat. Mat. 12, 1024 (2013).
[2] E. Berger et al., arxiv.org/abs/2010.03134 (2020)

Presenters

  • Emma Berger

    • University of California, Berkeley

Authors

  • Emma Berger

    • University of California, Berkeley

  • Sasawat Jamnuch

    • University of California, San Diego
    • University of California San Diego

  • Can Uzundal

    • University of California, Berkeley

  • Clarisse Woodahl

    • University of Florida

  • Hari Padmanabhan

    • Pennsylvania State University
    • Department of Material Science and Engineering, Penn State University

  • Angelique Amado

    • University of California, Berkeley

  • Paul Manset

    • Ecole Normale Superieure de Paris

  • Yasuyuki Hirata

    • National Defense Academy of Japan

  • Iwao Matsuda

    • The University of Tokyo

  • Venkatraman Gopalan

    • Pennsylvania State University
    • Material Science and Engineering, Pennsylvania State University
    • Department of Material Science and Engineering, Penn State University
    • Department of Materials Science and Engineering, Pennsylvania State University
    • Materials Science and Engineering, Pennsylvania State University

  • Yuya Kubota

    • RIKEN SPring-8 Center
    • Japan Synchrotron Radiation Research Institute

  • Shigeki Owada

    • RIKEN SPring-8 Center

  • Kensuke Tono

    • RIKEN SPring-8 Center

  • Makina Yabashi

    • RIKEN SPring-8 Center

  • Craig Schwartz

    • Lawrence Berkeley National Laboratory

  • Walter Drisdell

    • Lawrence Berkeley National Laboratory

  • John Freeland

    • argonne national laboratory
    • Argonne National Laboratory
    • Advanced Photon Source, Argonne National Laboratory
    • Argonne National Laboratory, Advanced Photon Source
    • Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA

  • Tod Pascal

    • University of California, San Diego
    • University of California San Diego

  • Michael Zuerch

    • University of California, Berkeley
    • Department of Chemistry, University of California Berkeley