Quantum transport simulations of nano-systems: an introduction to the Green's function approach (Invited contribution)
21st Century Nanoscience Book , Ed. K. Sattler, Vol. submitted, (2018)
Quantum transport simulations of nano-systems: an introduction to the Green's function approach (Invited contribution)
In this chapter we present a detailed treatment of coherent charge transport at the nano-scale. To begin with, we explain the Landauer-Buttiker theory and its underlaying assumptions. Then, we introduce the non-equilibrium Green's function (NEGF) technique, which provides a powerful framework to implement the theory for real device simualtions and to extend it beyond linear-response. The goal of the first part of the chapter is to provide the reader with the basic knowledge required to understand and implement a NEGF-based computational scheme for non-interacting tight-binding models. The second part of the chapter illustrates how NEGF can be combined with Density Functional Theory (DFT) to carry out first-principles simulations of molecular devices. We provide guidelines that will help the reader in performing practical DFT+NEGF simulations by using the most common implementation available in electronic structure software.