Inversion Symmetry Breaking Probed by X-ray Absorption Spectroscopy in H-bonded Organic Ferroelectric Crystal

ORAL

Abstract

Molecular ferroelectrics (FE) based on ordering hydrogen bonds have potentially high electric polarization and ordering temperature compared with the conventional oxide FE materials. In particular, croconic acid (C5O5H2) with FE polarization of 30 μC/cm2, plays a prototype of ferroelectric organic molecular solid, whose electric polarization is generated by proton transfer. We carry out X-ray absorption spectroscopy experiment at oxygen K-edge in croconic acid crystal. The experimental spectrum is well reproduced by the electron-hole excitation theory simulations from configuration generated by ab initio molecular dynamics simulation. When inversion symmetry is broken in ferroelectric state, the hydrogen bonding environment on the two bonded molecules become inequivalent. Such a difference is sensitively probed by the bound excitation in the pre-edge, which are strongly localized on the excited molecules. Our analysis shows that a satellite peak in the pre-edge will emerge at higher excitation energy which serves as a clear signature of ferroelectricity in the material.

*This work was primarily supported by National Science Foundation through Awards No. DMR-1552287.

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Presenters

  • Fujie Tang

    • Temple University
    • Department of Physics, Temple University

Authors

  • Fujie Tang

    • Temple University
    • Department of Physics, Temple University

  • Xuanyuan Jiang

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska

  • Hsin-Yu Ko

    • Cornell University
    • Department of Chemistry, Princeton University

  • Jianhang Xu

    • Temple University
    • Department of Physics, Temple University

  • Mehmet Topsakal

    • Center for Functional Nanomaterials, Brookhaven National Laboratory

  • Guanhua Hao

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska

  • Alpha T. N'Diaye

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Adv Light Source LBL

  • Peter A Dowben

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska - Lincoln
    • Department of Physics and Astronomy, University of Nebraska
    • Physics and Astronomy, University of Nebraska - Lincoln

  • Deyu Lu

    • Center for Functional Nanomaterials, Brookhaven National Laboratory

  • Xiaoshan Xu

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy and Nebraska Center for Materials and Nanoscience, University of Nebraska
    • Department of Physics and Astronomy, University of Nebraska - Lincoln
    • Physics & Astronomy, University of Nebraska-Lincoln
    • Department of Physics and Astronomy, University of Nebraska

  • Xifan Wu

    • Temple University
    • Department of Physics, Temple University