Official Resources
- Homepage: https://wien2wannier.github.io/
- Documentation: https://github.com/wien2wannier/wien2wannier/wiki
- Source Repository: https://github.com/wien2wannier/wien2wannier
- License: GNU General Public License (GPL)
Overview
WIEN2WANNIER is a specialized interface program that connects the high-precision, all-electron full-potential linearized augmented plane-wave (FP-LAPW) code WIEN2k with the maximally-localized Wannier function code Wannier90. It computes the necessary overlap matrices ($M_{mn}$) and projection matrices ($A_{mn}$) from WIEN2k's Bloch states, allowing for the construction of Wannier functions with all-electron accuracy. This tool is essential for researchers using methods that require a localized basis set (like DMFT or Berry Phase calculations) but demand the precision of LAPW.
Scientific domain: Condensed Matter Physics, Strongly Correlated Systems, Topological Materials
Target user community: Users of WIEN2k needing Wannier functions for post-processing
Theoretical Methods
- FP-LAPW Basis: Utilizes the highly accurate all-electron wavefunctions from WIEN2k (Planewaves + Atomic spheres).
- Projection: Projects Bloch states onto a set of trial localized orbitals (s, p, d, f types) to generate initial guesses ($A_{mn}$).
- Overlap Calculation: Computes the overlaps between periodic parts of Bloch functions ($M_{mn}$) on a Monkhorst-Pack mesh.
- Spin-Orbit Coupling: Full support for non-collinear and spin-orbit coupled calculations via spinor projections.
Capabilities
- Wannier90 Interface:
- Generates
.mmn (overlaps), .amn (projections), and .eig (eigenvalues) files.
- Supports disentanglement of entangled bands.
- All-Electron Accuracy: Captures core and semi-core effects crucial for d- and f-electron systems.
- Symmetry Handling: Uses WIEN2k symmetry operations to reduce computational cost.
- Real-Space Plotting: Tools to visualize Wannier functions constructed from the LAPW basis (
wplot).
Key Strengths
- Accuracy: As an interface to WIEN2k, it provides MLWFs based on the "gold standard" of DFT methods (FP-LAPW).
- f-electrons: Particularly strong for lanthanides and actinides where pseudopotentials may struggle.
- Integration: Tightly integrated into the WIEN2k workflow (callable via
x w2w).
Inputs & Outputs
- Inputs:
- WIEN2k structure (
case.struct) and vector files (case.vector).
- WIEN2WANNIER input file (
case.inw2w).
- Wannier90 input (
case.win).
- Outputs:
- Wannier90 required files:
case.mmn, case.amn, case.eig.
- Visualization data:
case.psZK, case.ploteig.
Interfaces & Ecosystem
- WIEN2k: Requires a working installation of WIEN2k.
- Wannier90: Generates inputs compatible with all modern versions of Wannier90.
- dmft_proj: Often used in conjunction with DMFT codes that interface with WIEN2k.
Performance Characteristics
- Computational Cost: The interface step itself is relatively inexpensive compared to the SCF cycle; scaling depends on the number of k-points and bands.
- Parallelism: Supports k-point parallelization consistent with WIEN2k's MPI scheme.
Limitations & Known Constraints
- Complexity: The LAPW basis is more complex than plane-waves, making the projection definition slightly more involved.
- Dependencies: Strictly tied to WIEN2k; cannot be used with other DFT codes.
- Memory: Overlap calculations for large systems/dense k-meshes can be memory-intensive.
Comparison with Other Codes
- vs. VASP2Wannier90: VASP uses PAW potentials; WIEN2WANNIER uses all-electron LAPW. WIEN2WANNIER is preferred for systems where core states or orthogonality orthogonality is critical (e.g., NMR, hyperfine parameters, heavy fermions).
- vs. SCAALD: Another interface for all-electron codes, but WIEN2WANNIER is the official/standard one for WIEN2k.
Application Areas
- Strongly Correlated Materials: DMFT studies of f-electron systems (Ce, Pu, U compounds).
- Topological Insulators: Accurate calculation of surface states and Berry curvature with SOC.
- Fermi Surface Analysis: High-precision Fermi surface interpolation via Wannier90.
Community and Support
- Development: Maintained by the Institute of Solid State Physics, TU Wien (Elias Assmann, Peter Blaha et al.).
- Mailing List: Support provided via the active WIEN2k mailing list.
- Updates: Regularly updated with WIEN2k releases (e.g., v2.0 in WIEN2k 16.1).
Verification & Sources
- Official Website: https://wien2wannier.github.io/
- Primary Publication: J. Kuneš et al., Comp. Phys. Commun. 181, 1888 (2010).
- Verification status: ✅ VERIFIED
- Integral part of the WIEN2k suite.
- Validated in numerous studies on f-electron dynamics.