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Internet Electronic Journal of Molecular Design - IEJMD, ISSN 1538-6414, CODEN IEJMAT
| ABSTRACT - Internet Electron. J. Mol. Des. August 2003, Volume 2, Number 8, 499-510 |
Computational Studies of Electronic Properties of ZrS2 Nanotubes
Victoria V. Ivanovskaya, Andrei N. Enyashin, Nadezhda I. Medvedeva, Yurii N. Makurin, and Alexander L. Ivanovskii
Internet Electron. J. Mol. Des. 2003, 2, 499-510
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Abstract:
The discovery of carbon nanotubes (NT) with unique properties
has stimulated the search for new quasi-one-dimensional (1D)
nanoscale inorganic materials (NTs, nanowires etc.). Numerous
d-metal dichalcogenide MX2 (M = Mo, W; X = S, Se) nanotubes
were prepared and investigated in the last decade. Quite recently
(2002) the first ZrS2 nanotubes were produced. As distinct from
the group V and VI metal disulfide NTs, the electronic properties
and chemical bonding of 1D nanomaterials based on group IV
metal (Ti, Zr and Ta) disulfides have not been studied up till
now. In the present paper, the electronic band structure and bond
indices of ZrS2 NTs were calculated for the first time and
analysed in comparison with other MS2 (M = Mo, W, Nb)
nanotubes. The electronic band structure, densities of states,
crystal orbital overlap populations and total band energies of
ZrS2 nanotubes and strips
(Etot) have been obtained using the
tight-binding band structure method. The atomic models of
zigzag- and armchair-like open-end ZrS2 nanotubes have been
constructed. The electronic structure and bond indices of ZrS2
nanotubes have been calculated and analysed as a function of the
tubes diameters (D) in the armchair- and zigzag-like forms. Our
calculations for the zigzag (n,0)- and
armchair (n,n)-like ZrS2
nanotubes (n = 8 ÷ 29) showed that all NTs with D > 2 nm are
uniformly semiconducting and their energy spectra are similar to
the DOS of the bulk ZrS2. The band gap tends to vanish as the
tube diameters decrease. Zr-S covalent bonds were found to be
the strongest interactions in ZrS2 tubes, whereas Zr-Zr bonds
prove to be much weaker, and the covalent S-S interactions are
absent (COOPs < 0). According to our results, the zigzag-like
configurations of the single-walled ZrS2 NTs are more stable.
Possible atomic structures of ZrS2 nanotube caps and ZrS2
fullerene-like molecules were also proposed and discussed.
Computer simulation of the band structure and bonding indices
of non-chiral ZrS2 nanotubes has been performed as the first step
to understand the electronic properties of 1D nanomaterials of
group IV d-metal disulfides which may be of interest, in
particular, as hydrogen-storage materials and insertion materials
of lithium batteries.
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