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Phonon spectra, electronic, and thermodynamic properties of WS 2 nanotubes
Author(s) -
Evarestov Robert A.,
Bandura Andrei V.,
Porsev Vitaly V.,
Kovalenko Alexey V.
Publication year - 2017
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.24916
Subject(s) - phonon , zigzag , raman spectroscopy , nanotube , materials science , heat capacity , condensed matter physics , helmholtz free energy , mechanical properties of carbon nanotubes , carbon nanotube , graphene , thermodynamics , nanotechnology , physics , optics , geometry , mathematics
Hybrid density functional theory calculations are performed for the first time on the phonon dispersion and thermodynamic properties of WS 2 ‐based single‐wall nanotubes. Symmetry analysis is presented for phonon modes in nanotubes using the standard (crystallographic) factorization for line groups. Symmetry and the number of infra‐red and Raman active modes in achiral WS 2 nanotubes are given for armchair and zigzag chiralities. It is demonstrated that a number of infrared and Raman active modes is independent on the nanotube diameter. The zone‐folding approach is applied to find out an impact of curvature on electron and phonon band structure of nanotubes rolled up from the monolayer. Phonon frequencies obtained both for layers and nanotubes are used to compute the thermal contributions to their thermodynamic functions. The temperature dependences of energy, entropy, and heat capacity of nanotubes are estimated with respect to those of the monolayer. The role of phonons in the stability estimation of nanotubes is discussed based on Helmholtz free energy calculations. © 2017 Wiley Periodicals, Inc.