Symmetry Conserving Maximally Projected Wannier Functions

Fuente: arXiv
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Main Authors: Koepernik, K., Janson, O., Sun, Yan, Brink, J. van den
Format: Preprint
Published: 2021
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author Koepernik, K.
Janson, O.
Sun, Yan
Brink, J. van den
author_facet Koepernik, K.
Janson, O.
Sun, Yan
Brink, J. van den
contents To obtain a local description from highly accurate density functional theory codes that are based on modified plane wave bases, a transformation to a local orthonormal Wannier function basis is required. In order to do so while enforcing the constraints of the space group symmetry the Symmetry Conserving Maximally Projected Wannier Functions (SCMPWF) approach has been implemented in the Full-Potential-Local-Orbital code, FPLO. SCMPWFs represent the zeroth order approximation to maximally localized Wannier functions, projecting a subset of wave functions onto a set of suitably chosen local trial-functions with subsequent orthonormalization. The particular nature of the local orbitals in FPLO make them an ideal set of projectors, since they are constructed to be a chemical basis. While in many cases projection onto the FPLO basis orbitals is sufficient, the option is there to choose particular local linear combinations as projectors, in order to treat cases of bond centered Wannier functions. This choice turns out to lead to highly localized Wannier functions, which obey the space group symmetry of the crystal by construction. Furthermore we discuss the interplay of the Berry connection and position operator and especially its possible approximation, symmetries and the optimal choice of Bloch sum phase gauge in cases where the basis is not explicitly known. We also introduce various features which are accessible via the FPLO implementation of SCMPWFs, discuss and compare performance and provide example applications.
format Preprint
id arxiv_https___arxiv_org_abs_2111_09652
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Symmetry Conserving Maximally Projected Wannier Functions
Koepernik, K.
Janson, O.
Sun, Yan
Brink, J. van den
Materials Science
To obtain a local description from highly accurate density functional theory codes that are based on modified plane wave bases, a transformation to a local orthonormal Wannier function basis is required. In order to do so while enforcing the constraints of the space group symmetry the Symmetry Conserving Maximally Projected Wannier Functions (SCMPWF) approach has been implemented in the Full-Potential-Local-Orbital code, FPLO. SCMPWFs represent the zeroth order approximation to maximally localized Wannier functions, projecting a subset of wave functions onto a set of suitably chosen local trial-functions with subsequent orthonormalization. The particular nature of the local orbitals in FPLO make them an ideal set of projectors, since they are constructed to be a chemical basis. While in many cases projection onto the FPLO basis orbitals is sufficient, the option is there to choose particular local linear combinations as projectors, in order to treat cases of bond centered Wannier functions. This choice turns out to lead to highly localized Wannier functions, which obey the space group symmetry of the crystal by construction. Furthermore we discuss the interplay of the Berry connection and position operator and especially its possible approximation, symmetries and the optimal choice of Bloch sum phase gauge in cases where the basis is not explicitly known. We also introduce various features which are accessible via the FPLO implementation of SCMPWFs, discuss and compare performance and provide example applications.
title Symmetry Conserving Maximally Projected Wannier Functions
topic Materials Science
url https://arxiv.org/abs/2111.09652