We have developed a practical scheme to construct partly occupied, maximally localized Wannier functions (WFs) for a wide range of systems. We explain and demonstrate how the inclusion of selected unoccupied states in the definition of the WFs can improve both their localization and symmetry properties. A systematic selection of the relevant unoccupied states is achieved by minimizing the spread of the resulting WFs. The method is applied to a silicon cluster, a copper crystal, and a Cu(100) surface with nitrogen adsorbed. In all cases we demonstrate the existence of a set of WFs with particularly good localization and symmetry properties, and we show that this set of WFs is characterized by a maximal average localization.
Bibliographical noteCopyright 2005 American Physical Society
Thygesen, K. S., Hansen, L. B., & Jacobsen, K. W. (2005). Partly occupied Wannier functions: Construction and applications. Physical Review B Condensed Matter, 72(12), 125119. https://doi.org/10.1103/PhysRevB.72.125119