Computational methods for density functional theory calculations on insulators and metals based on localised orbitals

Autor: Ruiz-Serrano, Alvaro
Rok vydání: 2013
Předmět:
Druh dokumentu: Electronic Thesis or Dissertation
Popis: Kahn-Sham density functional theory (OFT) calculations yield reliable accuracy in a wide variety of molecules and materials. The advent of linear-scaling OFT methods, based on locality of the electronic matter, has enabled calculations on systems with tens of thousands of atoms. Localisation constraints are imposed by expanding the Kahn-Sham states in terms of a set of atom-centred, spherically-localised functions. Chemical accuracy is then achieved via a self-consistent optimisation using a high-resolution basis set. This formalism reduces the size of, and brings predictable sparsity patterns to, the matrices expressed in this representation, such as the Hamiltonian matrix. In this work, we used the ONETEP program for DFT calculations, which is based on the abovementioncd principles. The vision behind our research is to advance the method by developing new and robust algorithms to enable novel applications based on localised orbitals.
Databáze: Networked Digital Library of Theses & Dissertations