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First‐principles modeling of hafnia‐based 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.24849
Subject(s) - hafnia , phonon , materials science , nanotube , helmholtz free energy , tetragonal crystal system , heat capacity , condensed matter physics , internal energy , thermodynamics , phase (matter) , nanotechnology , carbon nanotube , physics , composite material , quantum mechanics , cubic zirconia , ceramic
Hybrid density functional theory calculations were performed for the first time on structure, stability, phonon frequencies, and thermodynamic functions of hafnia‐based single‐wall nanotubes. The nanotubes were rolled up from the thin free layers of cubic and tetragonal phases of HfO 2 . It was shown that the most stable HfO 2 single‐wall nanotubes can be obtained from hexagonal (111) layer of the cubic phase. Phonon frequencies have been calculated for different HfO 2 nanolayers and nanotubes to prove the local stability and to find the thermal contributions to their thermodynamic functions. The role of phonons in stability of nanotubes seems to be negligible for the internal energy and noticeable for the Helmholtz free energy. Zone folding approach has been applied to estimate the connection between phonon modes of the layer and nanotubes and to approximate the nanotube thermodynamic properties. It is found that the zone‐folding approximation is sufficiently accurate for heat capacity, but less accurate for entropy. The comparison has been done between the properties of TiO 2 , ZrO 2 , and HfO 2 . © 2017 Wiley Periodicals, Inc.