Ab initio simulations on the atomic and electronic structure of single-walled BN nanotubes and nanoarches

Abstract

Ab initio simulations on the atomic and electronic structure of single-walled BN nanotubes and nanoarches,

Symmetry and Models of Single-Wall BN and TiO2 Nanotubes with Hexagonal Morphology

“…Calculated equilibrium lattice constants for the bulk of hexagonal BN structures have been found to be qualitatively close to their experimental values (a 0 of 2.51 Å vs 2.50 Å obtained in experiment and b 0 of 7.0 vs 6.7 Å 17 ), thus indicating reliable optimization of BN BSs. On the other hand, unlike the optical band gap energy ∆ε gap measured experimentally (5.96 eV for BN hex bulk 34 ) the value of ∆ε gap calculated by us is found to be noticeably larger (6.94 eV at K point of BZ) which is rather a result of the PBE0 hybrid functional application for BN calculations (since PWGGA functional gave a better agreement of these values 17 ). The small-core pseudopotential 35 of Ti atom is used in titania nanotube calculations (3s, 3p, 3d, and 4s-electrons were taken as valence electrons), while the all-electron BS for O-atom has been taken from ref 36.…”

“…24 This hexagonal structure can really exist in a metastable phase of bulk titania under extremely high pressure. 2 In this study, we perform comparative descriptions for hexagonal SW nanotubes for BN 17 and TiO 2 24 begun previously. In section 2, we consider the line group symmetry for these nanotubes.…”

Characterization of the Mechanical Properties of Monolayer Molybdenum Disulfide Nanosheets Using First Principles

“…Young's modulus is computed as the second derivative of the strain energy with respect to the strain, expressed by Eq. (1) [26,27] (1)…”

First‐principles calculations of point defects in inorganic nanotubes

“…In this study, we have performed the first‐principles simulations on doped NTs using the formalism of the localized Gaussian‐type functions (GTFs), which form the basis set (BS), and exploiting periodic rototranslation symmetry for efficient ground‐state calculations as implemented in the ab initio code CRYSTAL developing the formalism of localized atomic orbitals (LCAO) for calculations on periodic systems 29. Earlier, this approach was successfully applied by us for simulations on single‐ (SW) and multiwalled BN, TiO 2 , and STO NTs 20–27.…”

“…In this paper, we continue to present a series of results obtained using ab initio simulations on both perfect and defective BN NTs 20–23, as well as on perfect TiO 2 and STO NTs 24–27. Using hybrid exchange–correlation functionals applied within the density functional theory (DFT) we have calculated the following extrinsic isoelectronic substitutional impurities in BN NT: Al B , P N , Ga B , As N , In B , and Sb N as they may produce a strong effect in the luminescence spectra of nanostructured BN 12.…”