Lattice fluctuation induced pseudogap in quasi-one-dimensional Ta<sub>2</sub>NiSe<sub>5</sub>

ORAL

Abstract

In conventional solid-state systems, the development of an energy gap is often associated with a broken symmetry. However, strongly correlated materials can exhibit energy gaps without any global symmetry breaking -- the so-called pseudogap, most notably in the Mott insulating state and the fluctuating superconducting or charge density wave states. Combining angle-resolved photoemission spectroscopy (ARPES) and single crystal x-ray diffraction, we identify a pseudogap in the quasi-1D excitonic insulator candidate Ta2NiSe5. Strong lattice contribution is revealed by the pervasive diffuse scattering well above the transition temperature, and the negative electronic compressibility in the pseudogap state. Combining first-principles and microscopic model calculations, we show that inter-band electron-phonon coupling can create fluctuating phonon-mediated electron-hole pairs or hybridization, suppressing the spectral weight near EF and causing a metal-to-insulator like transition without breaking the global symmetry. This highlights Ta2NiSe5 as a promising room-temperature platform to study lattice-induced charge localization and low dimensional fluctuations.

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Presenters

  • Cheng Chen

    • University of Oxford

Authors

  • Cheng Chen

    • University of Oxford

  • Xiang Chen

    • Lawrence Berkeley National Laboratory

  • Weichen Tang

    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • University of California, Berkeley

  • Zhenglu Li

    • University of California at Berkeley, and Lawrence Berkeley National Laboratory
    • Physics Department, UC Berkeley and Lawrence Berkeley National Lab
    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory; University of California at Berkeley
    • University of California at Berkeley and Lawrence Berkeley National Laboratory

  • Siqi Wang

    • University of California, Berkeley
    • Yale University

  • shuhan ding

    • clemson university

  • Christopher Jozwiak

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • E. O. Lawrence Berkeley National Laboratory
    • lawrence berkeley lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory

  • Aaron Bostwick

    • Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Lab
    • E. O. Lawrence Berkeley National Laboratory
    • lawrence berkeley lab
    • Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley

  • Eli Rotenberg

    • Lawrence Berkeley National Laboratory

  • Makoto Hashimoto

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

  • Donghui Lu

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

  • Jacob Ruff

    • Cornell University

  • Steven G Louie

    • University of California at Berkeley, and Lawrence Berkeley National Laboratory
    • Physics Department, UC Berkeley and Lawrence Berkeley National Lab
    • University of California Berkeley
    • University of California, Berkeley
    • University of California at Berkeley; Lawrence Berkeley National Laboratory
    • University of California at Berkeley and Lawrence Berkeley National Laboratory
    • UC berkeley
    • University of California at Berkeley and Lawrence Berkeley National Lab
    • UC Berkeley & Lawrence Berkeley National Laboratory

  • Robert J Birgeneau

    • University of California, Berkeley

  • Yulin Chen

    • University of Oxford

  • Yao Wang

    • Clemson University
    • clemson university
    • Department of Physics and Astronomy, Clemson University

  • Yu He

    • Yale university
    • Yale University
    • yale university