Polarized Transient Reflectance Spectroscopy of Type II Weyl Semimetal NbIrTe<sub>4</sub>

ORAL

Abstract

Weyl semimetals have attracted intense interest for exhibiting chiral Fermion states. Strong nonlinear effects such as 2nd harmonic generation and DC photocurrents via circular photogalvanic effect are seen. Less understood is the dynamic response of said chiral carriers. We present polarized transient reflectance of single nanoflakes of NbIrTe4, employing ultrafast (140 fs) NIR pump and MIR probe pulses. We use a photo-elastic modulator to produce a ~50 kHz oscillation of the circular probe polarization from left to right handedness. DFT calculations predict the presence of 8 pairs of Weyl nodes with opposite chirality in the BZ of NbIrTe4. We observe a typical transient response composed of a rapid (~500 fs) decay followed by a slow (~1 ns) relaxation. A sign change in the transient response is observed at ~0.5 eV, suggestive of a band-to-band transition between a band below the Fermi energy and near the Weyl nodes to some higher-lying state.

*We acknowledge the financial support of the NSF through grants DMR 1507844, DMR 1531373, and ECCS 1509706. S.D.W. acknowledges the support of NSF DMR 1505549, and FZ acknowledges the support of the NSF of China through grant 11674278.

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Presenters

  • Samuel Linser

    • Univ of Cincinnati
    • Department of Physics, University of Cincinnati

Authors

  • Samuel Linser

    • Univ of Cincinnati
    • Department of Physics, University of Cincinnati

  • Giriraj Jnawali

    • Univ of Cincinnati
    • Department of Physics, University of Cincinnati

  • Seyyedesadaf Pournia

    • Univ of Cincinnati
    • Department of Physics, University of Cincinnati

  • Iraj Abbasian Shojaei

    • Univ of Cincinnati
    • Department of Physics, University of Cincinnati

  • Howard E Jackson

    • Department of Physics, University of Cincinnati

  • Leigh M Smith

    • Univ of Cincinnati
    • Department of Physics, University of Cincinnati
    • Physics, University of Cincinnati

  • Congcong Le

    • Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences
    • Kavli Institute of Theoretical Sciences, University of the Chinese Academy of Sciences

  • Fu-Chun Zhang

    • Kavli Institute of Theoretical Sciences, University of Chinese Academy of Sciences
    • University of Hong Kong
    • Kavli Institute of Theoretical Sciences, University of the Chinese Academy of Sciences
    • Kavli Institute for Theoretical Sciences, University of Chinese Academy of Sciences

  • Brenden Ortiz

    • University of California, Santa Barbara
    • Materials Engineering, University of California, Santa Barbara
    • Colorado School of Mines
    • California NanoSystems Institute/Materials, University of California, Santa Barbara

  • Stephen Wilson

    • University of California, Santa Barbara
    • Materials Department, University of California, Santa Barbara
    • Materials Engineering, University of California, Santa Barbara
    • California NanoSystems Institute/Materials, University of California, Santa Barbara