Angle and Polarization-Resolved Resonant Raman Spectroscopy of the Type-II Weyl Semimetal NbIrTe<sub>4</sub>

ORAL

Abstract

We perform polarized Raman spectroscopy measurements of single nanoflakes exfoliated from a single crystal of the layered ternary compound NbIrTe4. By varying the angle between the polarization direction of incident light and the crystalline “a” axis, spectra indicate strongly anisotropic Raman peaks which are consistent with the broken inversion symmetry of the crystal, which is an essential enabling condition for a type II Weyl semimetal. We have used both 633 nm and 514 nm laser excitation with incoming and backscattered rays parallel to the c-axis normal to the flake with the “a” and “b” axes in the plane of the nanoflake. The comparison of these spectra shows an enhancement of Raman peaks and also changes in rotational symmetry for 633 nm excitation. This suggest a possible unresolved resonance with a state at lower energies. Density Functional Theory (DFT) calculations of this crystal (space group Pmn21) show close correspondence with both the frequency and symmetries of the modes detected in our measurement.

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

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Presenters

  • Iraj Abbasian Shojaei

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

Authors

  • Iraj Abbasian Shojaei

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

  • Giriraj Jnawali

    • Univ of Cincinnati

  • Seyyedesadaf Pournia

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

  • Samuel Linser

    • Univ of Cincinnati

  • Howard Jackson

    • Univ of Cincinnati

  • Leigh Smith

    • Univ of Cincinnati

  • Congcong Le

    • Kavli Institute of Theoretical 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