Electronic and Vibrational Properties of New Polymorphs of NbS<sub>3</sub>: Phase-IV and Phase-V

ORAL

Abstract

Two new polymorphs of Niobium Trisulfide (NbS3), phase-IV and phase-V, have been grown and identified by single crystal x-ray diffraction. The polymorphs have monoclinic structure with space group P21/c and P21/m, respectively. We have calculated the electronic and vibrational properties of both polymorphs, using ab initio density function theory (DFT) at the PBE and HSE level of theory. Electronic band calculation suggests that phase-IV is a semiconductor with an indirect bandgap of ~0.2 eV (PBE), whereas phase-V is a metal. The phonon energy at the zone-center matches closely with the measured Raman spectra. Moreover, the full phonon dispersion reveals that phase-IV is dynamically stable (no negative phonon branches). On the contrary, phase-V exhibits several negative phonon pockets, specifically along the NbS3 nanowire growth direction. This is an indicator of a possible charge density wave (CDW) ground state in this polymorph.

*This work is supported in part by the Emerging Frontiers of Research Initiative (EFRI) 2-DARE project: Novel Switching Phenomena in Atomic MX2 Heterostructures for Multifunctional Applications (NSF EFRI-1433395), and the Extreme Science and Engineering Discovery Environment (XSEDE) by NSF Gran

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Presenters

  • Bishwajit Debnath

    • Electrical and computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California, Riverside
    • Department of Electrical and Computer Engineering, University of California, Riverside
    • Department of Electrical and Computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California Riverside

Authors

  • Bishwajit Debnath

    • Electrical and computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California, Riverside
    • Department of Electrical and Computer Engineering, University of California, Riverside
    • Department of Electrical and Computer Engineering, Univ of California - Riverside
    • Electrical and Computer Engineering, University of California Riverside

  • Mathew Bloodgood

    • Chemsitry, University of Georgia
    • Department of Chemistry, University of Georgia

  • Ece Aytan

    • Electrical and computer Engineering, Univ of California - Riverside
    • Department of Electrical and Computer Engineering, University of California, Riverside
    • Electrical and Computer Engineering, University of California, Riverside
    • Material Science and Engineering, University of California Riverside

  • Tina Salguero

    • Chemsitry, University of Georgia
    • Department of Chemistry, University of Georgia

  • Alexander Balandin

    • Electrical and Computer Engineering , University of California
    • Electrical and Computer Engineering, University of California Riverside
    • Electrical and computer Engineering, Univ of California - Riverside
    • Department of Electrical and Computer Engineering/Materials Science and Engineering Program, University of California, Riverside
    • Department of Electrical and Computer Engineering, University of California, Riverside
    • Electrical and Computer Engineering, University of California, Riverside
    • University of California Riverside

  • Roger Lake

    • Department of Electrical and Computer Engineering, University of California, Riverside
    • EE, Univ of California - Riverside
    • Electrical and computer Science engineering, University of California Riverside
    • University of California, Riverside