Modeling of nanostructures and nanomaterials
Nanostructured materials (NSM) as a subject of contemporary nanotechnology are low-dimensional structures comprising building units of nanoscale size and exhibiting size’s effects. NSM are defined formally as the structures at least one size of which (d) is less or equal to a critical one (d*), i.e., d < d* 102 nm. The value of d* possesses not a certain magnitude because it is dictated physically by a critical characteristic of physical phenomena (a free path length of electrons or phonons, length of de Broglie wave, length of external electromagnetic or acoustical waves, diffusion length, etc.) giving a rise to the size’s effects. Neglecting peculiarities of the internal structure all NSM can be sort out by the dimensionality: 0D, 1D, 2D, and 3D. All NSM can be built from elementary blocks having a lower dimensionality. For example, 3D structures can be considered as NSM if they involve the 0D, 1D, and 2D nanostructures as building blocks. We also exclude 2D nanostructures from our current consideration and description since except for a few simplest types of 2D NSM (e.g., graphene-like monolayers) their comprehensive systematization is still problematic. The most effective strategy for study of 0D&1D NSM include their synthesis, determination of their structure and properties as well as modeling (Fig. 1). If both shapes and internal structure of NSM models are highly-symmetric they are more fitted for the effective modeling. Thus, the proper application of symmetry groups for description of nanostructures is one of the key points.
We have performed the large-scale first principles calculations on a few inorganic 1D nanostructures: (a) the single-wall (SW) AlN and BN nanotubes (NTs) with hexagonal morphology, both perfect [1] and defective [2]; (b) the four sets of SW TiO2 NTs with optimized 6- and 3-layer structures (which belong to either centered rectangular or hexagonal morphologies, i.e., possessing either anatase or fluorite chiralities, respectively); several configurations of double-wall (DW) titania nanotubes have been simulated too; (c) the 2D models of SW CNT bundles containing finite nanotubes of two types of chiralities grown on both smooth and nanostructured Ni(111) surface have been simulated using large-scale ab initio calculations; the electric properties of the CNT-metal interconnects have been simulated too [3]. We also simulate DW CNTs combining different types of chirality, using both ab initio and semi-empirical methods.
References:
1. Yu.F. Zhukovskii, S. Piskunov, N. Pugno, B. Berzina, L. Trinkler, S. Bellucci, Ab initio simulations on the atomic and electronic structure of single-walled BN nanotubes and nanoarches. - J. Phys. Chem. Solids, 2009, 70, p. 796-803.
2.Yu.F. Zhukovskii, N. Pugno, A.I. Popov, C. Balasubramanian, S. Bellucci, Influence of F centers on structural and electronic properties of AlN single-walled nanotubes. - J. Phys.: Cond. Matter, 2007, 19, 395021 (p. 1-18).
3.Yu.N. Shunin, Yu.F. Zhukovskii, V.I. Gopeyenko, N. Shunina, Theoretical simulations on nanoelectronic devices: quantum dots, nanowires and carbon nanotubes. - Proc. 9th Int. Conf. Reliability&Statistics in Transportation&Communication, RelStat'09 (Riga), 2009, p. 413-423.