title: High Pressure Vibrational Properties of WS2 Nanotubes.
abstract: We bring together synchrotron-based infrared and Raman spectroscopies, diamond anvil cell techniques, and an analysis of frequency shifts and lattice dynamics to unveil the vibrational properties of multiwall WS2 nanotubes under compression. While most of the vibrational modes display similar hardening trends, the Raman-active A1g breathing mode is almost twice as responsive, suggesting that the nanotube breakdown pathway under strain proceeds through this displacement. At the same time, the previously unexplored high pressure infrared response provides unexpected insight into the electronic properties of the multiwall WS2 tubes. The development of the localized absorption is fit to a percolation model, indicating that the nanotubes display a modest macroscopic conductivity due to hopping from tube to tube.
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: K R
authors.initials: KR
authors.lastname: O'Neal
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: J G
authors.initials: JG
authors.lastname: Cherian
authors.affiliation: Faculty of Sciences, Holon Institute of Technology , Holon 58102, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Zak
authors.affiliation: Department of Materials and Interfaces, Weizmann Institute , Rehovot 76100, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Tenne
authors.affiliation: Geophysical Laboratory, Carnegie Institution of Washington , Washington D.C. 20015, United States.
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.
authors.forename: J L
authors.initials: JL
authors.lastname: Musfeldt
keywords: WS2 nanotubes; high pressure vibrational spectroscopies; nanoscale transition metal dichalcogenides; percolation