Partly Occupied Wannier Functions

TL;DR

This paper presents a new scheme for constructing partly occupied, maximally localized Wannier functions that improve symmetry and localization, applicable to molecular and periodic systems, demonstrated on benzene, platinum chains, and a Pt wire with hydrogen.

Contribution

The paper introduces a bonding-antibonding closing procedure for partly occupied Wannier functions, enhancing their symmetry and localization properties.

Findings

Bonding-antibonding closure is equivalent to spread minimization for certain systems.

The method improves Wannier functions for metallic systems with impurities.

Demonstrated applicability to molecules, periodic chains, and impurity systems.

Abstract

We introduce a scheme for constructing partly occupied, maximally localized Wannier functions (WFs) for both molecular and periodic systems. Compared to the traditional occupied WFs the partly occupied WFs posses improved symmetry and localization properties achieved through a bonding-antibonding closing procedure. We demonstrate the equivalence between bonding-antibonding closure and the minimization of the average spread of the WFs in the case of a benzene molecule and a linear chain of Pt atoms. The general applicability of the method is demonstrated through the calculation of WFs for a metallic system with an impurity: a Pt wire with a hydrogen molecular bridge.