Ab-initio non-equilibrium quantum transport and forces with the real space projector augmented wave method

TL;DR

This paper introduces an efficient NEGF-DFT implementation using the PAW method for non-equilibrium quantum transport and forces in nanostructures, enabling large-scale simulations with bias and gate voltages.

Contribution

It presents a novel, efficient real-space NEGF-DFT approach with PAW and atomic orbitals, capable of handling large nanostructures under non-equilibrium conditions.

Findings

Demonstrated effects of bias and gate voltages on transport properties

Enabled simulations of systems with hundreds of atoms

Analyzed non-equilibrium forces and spin transport phenomena

Abstract

We present an efficient implemention of a non-equilibrium Green function (NEGF) method for self-consistent calculations of electron transport and forces in nanostructured materials. The electronic structure is described at the level of density functional theory (DFT) using the projector augmented wave method (PAW) to describe the ionic cores and an atomic orbital basis set for the valence electrons. External bias and gate voltages are treated in a self-consistent manner and the Poisson equation with appropriate boundary conditions is solved in real space. Contour integration of the Green function and parallelization over k-points and real space makes the code highly efficient and applicable to systems containing several hundreds of atoms. The method is applied to a number of different systems demonstrating the effects of bias and gate voltages, multiterminal setups, non-equilibrium forces, and spin transport.