First-principles methodology for quantum transport in multiterminal junctions

TL;DR

This paper introduces a first-principles method for calculating electron transport properties in multiterminal junctions, enabling detailed analysis of complex electronic devices.

Contribution

The paper develops a generalized, self-consistent approach within Keldysh theory for multiterminal systems, using an efficient O(N) electronic-structure calculation method.

Findings

Successfully applied to four-terminal systems demonstrating charge density and transmission analysis.

Provides a framework for studying complex electronic devices with multiple terminals.

Shows the method's effectiveness in modeling realistic bias conditions.

Abstract

We present a generalized approach for computing electron conductance and I-V characteristics in multiterminal junctions from first-principles. Within the framework of Keldysh theory, electron transmission is evaluated employing an O(N) method for electronic-structure calculations. The nonequilibrium Green function for the nonequilibrium electron density of the multiterminal junction is computed self-consistently by solving Poisson equation after applying a realistic bias. We illustrate the suitability of the method on two examples of four-terminal systems, a radialene molecule connected to carbon chains and two crossed carbon chains brought together closer and closer. We describe charge density, potential profile, and transmission of electrons between any two terminals. Finally, we discuss the applicability of this technique to study complex electronic devices.