Calculation of the Green's function in the scattering region for first-principles electron-transport simulations

We propose a first-principles method of efficiently evaluating electron-transport properties of very long systems. Implementing the recursive Green's function method and the shifted conjugate gradient method in the transport simulator based on real-space finite-difference formalism, we can suppress the increase in the computational cost, which is generally proportional to the cube of the system length to a linear order. This enables us to perform the transport calculations of double-walled carbon nanotubes (DWCNTs) with 196 608 atoms. We find that the conductance spectra exhibit different properties depending on the periodicity of doped impurities in DWCNTs and they differ from the properties for systems with less than 1000 atoms.

Automated summary

A method for efficiently evaluating electron-transport properties of very long systems was proposed, utilizing specific algorithms to reduce computational costs and perform transport calculations on double-walled carbon nanotubes containing 196608 atoms. The study found that the periodicity of doped impurities in DWCNTs can affect the conductance spectra properties.