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

Bishwajit Debnath; Mathew Bloodgood; Ece Aytan; Tina Salguero; Alexander Balandin; Roger Lake

Electronic and Vibrational Properties of New Polymorphs of NbS₃: 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 P2_1/c and P2_1/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.

March 7, 2018, 6:42 PM – March 7, 2018, 6:54 PM

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