Theory Guide

This guide provides the theoretical background for the gauNEGF package.

Theory Topics

• Introduction to NEGF-DFT
  • Historical Context
  • Core Functionality
  • Mathematical Framework
  • Key Equations
  • Contact Models and Testing
  • Next Steps
  • References
• Self-Consistent NEGF-DFT
  • Theory Overview
  • Implementation Classes
  • Mathematical Details
  • Implementation
  • Practical Considerations
  • Example Workflows
  • Next Steps
• Transport Calculations
  • Transmission Function
  • Current Calculations
  • Spin-Dependent Transport
  • Analysis Tools
  • Example Analysis
  • Next Steps
• Best Practices for Production Calculations
  • System Preparation
  • DFT Setup
  • Convergence Strategies
  • Troubleshooting Guide

Overview

gauNEGF implements Non-Equilibrium Green’s Function (NEGF) calculations with Density Functional Theory (DFT) using Gaussian basis sets. The key theoretical components are:

1. NEGF Formalism

   • Green’s functions in quantum transport

   • Self-energy and contact effects

   • Current and transmission calculations

2. DFT Integration

   • Density matrix construction

   • Self-consistent field iterations

   • Basis set considerations

3. Transport Theory

   • Landauer-Büttiker formalism

   • Coherent transport

   • Spin-dependent transport

Getting Started

For a structured approach to understanding the theory:

1. Start with Introduction to NEGF-DFT for basic concepts and system setup

2. Dive into Self-Consistent NEGF-DFT for detailed methodology

3. Explore Transport Calculations for transport calculations

4. Review Best Practices for Production Calculations for optimal usage