Abstract
We discuss a method for determining the optimally localized set of generalized Wannier functions associated with a set of Bloch bands in a crystalline solid. By “generalized Wannier functions” we mean a set of localized orthonormal orbitals spanning the same space as the specified set of Bloch bands. Although we minimize a functional that represents the total spread of the Wannier functions in real space, our method proceeds directly from the Bloch functions as represented on a mesh of points, and carries out the minimization in a space of unitary matrices describing the rotation among the Bloch bands at each point. The method is thus suitable for use in connection with conventional electronic-structure codes. The procedure also returns the total electric polarization as well as the location of each Wannier center. Sample results for Si, GaAs, molecular CH, and LiCl will be presented.
- Received 10 July 1997
DOI:https://doi.org/10.1103/PhysRevB.56.12847
©1997 American Physical Society