# Multi-scale approach to first-principles electron transport beyond 100 nm

## TL;DR

This paper introduces a multi-scale computational method combining DFT and tight-binding models to simulate electron transport in large 2D devices over 100 nm, capturing atomistic details and complex device features.

## Contribution

The paper presents a novel multi-scale approach that integrates DFT and tight-binding models for large-scale 2D electron transport simulations beyond 100 nm.

## Key findings

- Successfully applied to pristine, defected, and nanoporous graphene devices
- Enabled atomistic-level current propagation analysis in large devices
- Addressed practical implementation challenges of multi-scale modeling

## Abstract

Multi-scale computational approaches are important for studies of novel, low-dimensional electronic devices since they are able to capture the different length-scales involved in the device operation, and at the same time describe critical parts such as surfaces, defects, interfaces, gates, and applied bias, on a atomistic, quantum-chemical level. Here we present a multi-scale method which enables calculations of electronic currents in two-dimensional devices larger than 100 nm$^2$, where multiple perturbed regions described by density functional theory (DFT) are embedded into an extended unperturbed region described by a DFT-parametrized tight-binding model. We explain the details of the method, provide examples, and point out the main challenges regarding its practical implementation. Finally we apply it to study current propagation in pristine, defected and nanoporous graphene devices, injected by chemically accurate contacts simulating scanning tunneling microscopy probes.