Using ONETEP for accurate and efficient O(N) density functional calculations

We present a detailed comparison between ONETEP, our linear-scaling density functional method, and the conventional pseudopotential plane wave approach in order to demonstrate its high accuracy. Further comparison with all-electron calculations shows that only the largest available Gaussian basis sets can match the accuracy of routine ONETEP calculations. Results indicate that our minimisation procedure is not ill-conditioned and that convergence to self-consistency is achieved efficiently. Finally we present calculations with ONETEP, on systems of about 1000 atoms, of electronic, structural and chemical properties of a wide variety of materials such as metallic and semiconducting carbon nanotubes, crystalline silicon and a protein complex.