This tutorial introduces you to one of the most important functionalities in Atomistix ToolKit (ATK) - transport calculations. The system you will investigate is a hydrogen molecule placed between two one-dimensional lithium wires. This system is selected for demonstration purposes, in order to make calculations very fast. However, it does encapsulate many of the relevant and interesting physical effects present in more realistic systems, and these will be discussed in the tutorial. For more interesting physical systems, you are refered to the more comprehensive tutorials available from our website.

The calculations will be carried out using density-functional theory (DFT) (for the electronic structure part) in combination with non-equillibrium Green's function (NEGF) techniques (for the transport part). A longer description of some more technical aspects of the parameters and models can be found in the ATK reference manual,

To set up the structures and calculations you will use the graphical interface Virtual NanoLab (VNL). It is recommended to first go through the introduction tutorial for VNL, just to become familiar with the fundamental concepts and how to operate the software.

The first step of the tutorial is to set up the geometry.