Wannier functions

In this tutorial, we will learn how to construct Wannier functions from SIESTA using the SIESTA-Wannier90 interface. The knowledge of Maximally localized Wannier function (MLWF) is assumed. The readers can refer to the review paper on MLWF [MLWF] , and the resources on the Wannier90 website .

We will first learn how to prepare the input files for SIESTA and Wannier90 with the example of Wannierization of valence and conduction bands of \(SrTiO_3\). Then we’ll move to a slightly more complex example, where the disentanglement is needed. Finally, we will try one application of the Wannier function: plotting of the Fermi surface.

Note

Compilation of Siesta-Wannier is not covered in the installation section.

• Preparing interface between SIESTA and Wannier90 (example: \(SrTiO_3\))
• Disentanglement (example: graphene)
• Plotting of Fermi surface with Wannier functions (example: \(SrTiO_3\))

Note

This is the traditional way of doing things. There is a new method, not yet released officially, in which the wannier90 code is used directly by Siesta in library mode.

MLWF

Nicola Marzari, Arash A. Mostofi, Jonathan R. Yates, Ivo Souza, and David Vanderbilt, Maximally localized Wannier functions: Theory and applications. Rev. Mod. Phys. 84, 1419 (2012) .