Quasicontinuum-Like Reduction of Density Functional Theory Calculations of Nanostructures
D. Negrut, M. Anitescu, A. El-Azab and P. Zapol
Journal of Nanoscience and Nanotechnology, 8, 3729-3740 (2008).
ABSTRACT
Density functional theory can accurately predict chemical and mechanical
properties of nanostructures, although at a high computational cost. A
quasicontinuum-like framework is proposed to substantially increase the size of
the nanostructures accessible to simulation. It takes advantage of the near
periodicity of the atomic positions in some regions of nanocrystalline materials
to establish an interpolation scheme for the electronic density in the system.
The electronic problem embeds interpolation and coupled cross-domain
optimization techniques through a process called electronic reconstruction. For
the optimization of nuclei positions, computational gains result from explicit
consideration of a reduced number of representative nuclei and interpolating the
positions of the rest of nuclei following the quasicontinuum paradigm. Numerical
tests using the Thomas-Fermi-Dirac functional demonstrate the validity of the
proposed framework within the orbital-free density functional theory.