TY - JOUR

T1 - First-principles modeling of hafnia-based nanotubes

AU - Evarestov, Robert A.

AU - Bandura, Andrei V.

AU - Porsev, Vitaly V.

AU - Kovalenko, Alexey V.

PY - 2017/9/15

Y1 - 2017/9/15

N2 - 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 HfO2. It was shown that the most stable HfO2 single-wall nanotubes can be obtained from hexagonal (111) layer of the cubic phase. Phonon frequencies have been calculated for different HfO2 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 TiO2, ZrO2, and HfO2.

AB - 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 HfO2. It was shown that the most stable HfO2 single-wall nanotubes can be obtained from hexagonal (111) layer of the cubic phase. Phonon frequencies have been calculated for different HfO2 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 TiO2, ZrO2, and HfO2.

KW - hafnia

KW - nanolayers

KW - phonon frequencies

KW - strain energy

KW - thermodynamic properties

KW - zone folding

UR - http://www.scopus.com/inward/record.url?scp=85020717639&partnerID=8YFLogxK

U2 - 10.1002/jcc.24849

DO - 10.1002/jcc.24849

M3 - Article

AN - SCOPUS:85020717639

VL - 38

SP - 2088

EP - 2099

JO - Journal of Computational Chemistry

JF - Journal of Computational Chemistry

SN - 0192-8651

IS - 24

ER -