Efficient partitioning of surface Green's function: toward ab initio contact resistance study

TL;DR

This paper introduces a novel, efficient computational method for quantum transport simulations that constructs contact self-energy matrices on smaller building blocks, significantly improving efficiency while maintaining accuracy.

Contribution

The proposed partitioning scheme for Green's function calculations differs from traditional methods by using principal layers, enabling faster simulations in first-principles contact resistance studies.

Findings

Achieved significant computational efficiency improvements.

Accurately evaluated contact resistances in silicon nanowire devices.

Validated method through NEGF-based simulations.

Abstract

In this work, we propose an efficient computational scheme for first-principle quantum transport simulations to evaluate the open-boundary conditions. Its partitioning differentiates from conventional methods in that the contact self-energy matrices are constructed on smaller building blocks, principal layers (PL), while conventionally it was restricted to have the same lateral dimensions of the adjoining atoms in a channel region. Here, we obtain the properties of bulk electrodes through non-equilibrium Green's function (NEGF) approach with significant improvements in the computational efficiency without sacrificing the accuracy of results. To exemplify the merits of the proposed method we investigate the carrier density dependency of contact resistances in silicon nanowire devices connected to bulk metallic contacts.