Wannier90

Wannier90
Name	Wannier90
Latest release	3.4.0
Programming language	Fortran90, Python
Operating system	Linux, macOS, Windows (via WSL)
License	GNU General Public License

Wannier90 is an open-source software package for computing maximally-localized Wannier functions and related quantities from electronic-structure calculations. The project is widely used to extract tight-binding models, interpolate band structures, and compute electronic properties from first-principles codes such as Quantum ESPRESSO, VASP, ABINIT, WIEN2k, and FHI-aims. It is developed and maintained by an international collaboration involving institutions like Cavendish Laboratory, EPFL, and University of Cambridge.

Overview

Wannier90 provides tools to transform Bloch states produced by plane-wave and all-electron codes into localized functions named after Gregory Wannier. The package implements the Marzari–Vanderbilt procedure introduced in a landmark paper by Nicola Marzari and David Vanderbilt, which is central to the modern theory of polarization developed by R. D. King-Smith and D. Vanderbilt. Wannier90 interoperates with pseudopotential libraries such as PSLIB and with community infrastructures like Materials Project and NOMAD to enable high-throughput workflows.

Theory and Methodology

The code operationalizes the theory of maximally-localized Wannier functions using gauge-fixing and spread minimization, building on concepts from Bloch's theorem, the Berry phase formalism, and the modern theory of polarization. It employs disentanglement algorithms related to work by Ivo Souza, Nicola Marzari, and David Vanderbilt to treat entangled bands, and uses real-space localization metrics drawing from research by Emmanuel Prodan and Raffaele Resta. Wannier90 computes matrix elements of operators like the Hamiltonian and velocity operator to construct tight-binding Hamiltonians that connect to studies by Philip Phillips and Walter Kohn.

Implementation and Features

Wannier90 is implemented in Fortran90 with auxiliary Python scripts and offers features such as maximal localization, disentanglement, symmetry adaptation using representations from International Tables for Crystallography, and post-processing modules for band interpolation. It produces output formats compatible with visualization tools like VESTA and XCrySDen and supports interpolation schemes used in calculations of anomalous Hall conductivity studied by N. Nagaosa and Qian Niu. The package includes utilities for computing Wannier charge centers, Berry curvature, orbital character projections, and spin-orbit-coupled Wannier functions relevant to research by Eugene Mele and Charles Kane.

Interfacing and Workflows

Wannier90 interfaces through standardized input/output drivers with electronic-structure packages including Quantum ESPRESSO, VASP, ABINIT, WIEN2k, FHI-aims, CP2K, and SIESTA. Workflow integration is common with workflow managers and platforms such as ASE (Atomic Simulation Environment), AiiDA, FireWorks, AFLOW, and Materials Cloud, enabling reproducible pipelines akin to initiatives by Mark Thompson and Gerbrand Ceder. The package supports exporting tight-binding models to simulators like Kwant and tools used in topology research exemplified by Alexei Kitaev and Shoucheng Zhang.

Applications

Researchers use Wannier90 across condensed-matter and materials science problems, including electron transport studies inspired by Rolf Landauer, topological band-structure analysis following landmark works by Charles Kane and Shou-Cheng Zhang, superconductivity model building related to B. D. Josephson and Philip W. Anderson, and dielectric response quantified through theories developed by R. Resta. It is instrumental in high-throughput materials discovery efforts coordinated with Materials Project and Open Quantum Materials Database and in interpreting experiments from facilities like Diamond Light Source and European Synchrotron Radiation Facility.

Development and Community

The Wannier90 project is stewarded by contributors from universities and national laboratories including Cavendish Laboratory, EPFL, CEA, and Oak Ridge National Laboratory. Development follows open-source practices with version control and collaborative code review influenced by workflows used at GitHub and community governance models similar to Linux Foundation projects. Training and dissemination occur via workshops at conferences such as ICMSE and schools organized by CMM and Psi-k.

Performance and Benchmarks

Wannier90's performance depends on k-point sampling, band count, and disentanglement complexity; benchmarking often compares runtime and memory against plane-wave operations in Quantum ESPRESSO or projector-augmented wave workflows in VASP. Parallelization strategies reflect best practices used in high-performance computing centers like NERSC and Jülich Supercomputing Centre, and scaling studies reference algorithms from computational science literature including work by Sergio Goedecker and François Gygi. Typical benchmarks report efficient interpolation of dense Brillouin-zone meshes enabling calculations of Fermi surfaces and transport coefficients validated against experimental results from APS beamlines.

Category:Electronic structure software