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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