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Light-induced coherent modulation of the electrons and lattice in a charge density wave material

ORAL

Abstract

Ultrashort light pulses can selectively excite charges, spins and phonons in materials, providing a powerful approach for manipulating their properties. In this work, we use time- and angle-resolved photoemission spectroscopy to show that a femtosecond laser pulse can coherently modulate the electrons and lattice in the charge density wave (CDW) material 1T-TaSe2 [1, 2]. These intertwined electron-phonon dynamics are launched by displacive excitation of the CDW amplitude mode, and provide unique opportunities to capture mode-specific electron-phonon couplings, interatomic potentials, and hidden phases that are inaccessible using equilibrium excitation. Surprisingly, we observe a coherent modulation of the electron temperature/occupation at the amplitude mode frequency, that is synchronized to the modulation of the Ta 5d band (CDW order). Then, as we increase the laser fluence to drive the material into a metastable state mediated by mode-selective electron-phonon coupling, this oscillation exhibits a phase change of p, indicating a competition between different interactions. This approach can be extended to other complex materials, to steer strongly-coupled quantum materials towards a desired state using light.
[1] Science Advances 5, eaav4449 (2019).
[2] arXiv:1906.09545.

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Presenters

  • Xun Shi

    JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder

Authors

  • Xun Shi

    JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder

  • Wenjing You

    JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder

  • Yingchao Zhang

    JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder

  • Zhensheng Tao

    Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder

  • Yigui Zhong

    Department of Physics and JILA, University of Colorado, Boulder, University of Colorado, Boulder

  • Xianxin Wu

    Institute for Theoretical Physics, University of Wuerzburg, Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Physics department, Pennsylvania State University, University of Wurzburg, Institut für Theoretische Physik und Astrophysik, University of Würzburg

  • Ronny Thomale

    University of Wurzburg, Institute for Theoretical Physics, University of Wuerzburg, Theoretical physics I, University of Wuerzburg, University of Wuerzburg, Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Physics department, University of Wuerzburg, Institut für Theoretische Physik und Astrophysik, University of Würzburg, Institute for Theoretical Physics and Astrophysics, University of Wurzburg

  • Fairoja Cheenicode Kabeer

    Uppsala University

  • Pablo Maldonado

    Uppsala University

  • Peter Oppeneer

    Department of Physics and Astronomy, Uppsala University, Uppsala University

  • Michael Bauer

    Institute of Experimental and Applied Physics, Kiel University, University of Kiel, Kiel University

  • Kai Rossnagel

    Christian-Albrechts-Universitat zu Kiel, Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität zu Kiel, 24098 Kiel, Germany, Institute of Experimental and Applied Physics, Kiel University, Kiel University, University of Kiel

  • Henry Kapteyn

    JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, STROBE and JILA, University of Colorado, Boulder, JILA and Department of Physics, University of Colorado, Boulder, STROBE and JILA, University of Colorado and NIST, Physics, JILA/University of Colorado Boulder, JILA, University of Colorado, Boulder, Physics and JILA, CU Boulder, JILA, University of Colorado, Boulder

  • Margaret Murnane

    JILA, University of Colorado Boulder, Department of Physics and JILA, University of Colorado, Boulder, STROBE and JILA, University of Colorado, Boulder, STROBE and JILA, University of Colorado and NIST, JILA, University of Colorado, Boulder, Physics and JILA, CU Boulder, University of Colorado, JILA, University of Colorado, Boulder