WIEN2k-Topo

Official Resources

• Publication: Comput. Phys. Commun. (2023), doi:10.1016/j.cpc.2023.108836
• arXiv: https://arxiv.org/abs/2303.16306
• Data: Zenodo repository
• License: Check with authors

Overview

WIEN2k-Topo comprises two Python modules (CherN.py and wcc.py) that expand the functionalities of the all-electron full-potential WIEN2k package for computing Chern and Z2 topological invariants. These complement the WloopPHI module to provide a complete toolkit for topological characterization.

Scientific domain: Topological invariants, all-electron calculations, band topology Target user community: WIEN2k users studying topological materials

Theoretical Methods

• Chern number calculation via Berry curvature integration
• Z2 invariant from hybrid Wannier charge centers (WCC)
• Wilson loop evolution tracking
• Fu-Kane parity method for inversion-symmetric systems
• All-electron LAPW accuracy

Capabilities (CRITICAL)

• Chern Number: Berry curvature integration method
• Z2 Invariant: WCC evolution method
• WIEN2k Native: Direct interface with WIEN2k
• All-Electron: Full-potential LAPW accuracy
• Validated: Tested on known topological materials
• WloopPHI Compatible: Works with existing WIEN2k topology tools

Sources: CPC publication, arXiv preprint

Key Strengths

All-Electron Accuracy:

• Full-potential LAPW method
• Core electron treatment
• High accuracy for heavy elements
• Spin-orbit coupling included

Complete Toolkit:

• Combines with WloopPHI
• Chern and Z2 together
• Multiple methods available
• Cross-validation possible

WIEN2k Integration:

• Native WIEN2k interface
• Uses WIEN2k wavefunctions
• Consistent workflow
• Established DFT package

Inputs & Outputs

• Input formats:

  • WIEN2k case files
  • Band structure data
  • k-mesh specification

• Output data types:

  • Chern numbers
  • Z2 invariants
  • WCC evolution plots
  • Berry curvature data

Installation

# Obtain from Zenodo repository
# Place in WIEN2k SRC directory
# Configure for your WIEN2k installation

Usage Examples

# After WIEN2k SCF calculation
# Calculate Chern number
python CherN.py -case material -kx 20 -ky 20

# Calculate Z2 invariant via WCC
python wcc.py -case material -plane kz0 -nk 50

Performance Characteristics

• Speed: Depends on k-mesh density
• Accuracy: All-electron precision
• Scalability: Handles complex materials

Limitations & Known Constraints

• WIEN2k-specific: Requires WIEN2k installation
• k-mesh density: Dense mesh needed for accuracy
• Computational cost: All-electron is expensive

Comparison with Other Tools

• vs Z2Pack: WIEN2k-Topo all-electron, Z2Pack general
• vs WannierTools: Different DFT backends
• Unique strength: All-electron accuracy with WIEN2k

Application Areas

• Topological insulator identification
• Chern insulator classification
• Heavy element topological materials
• Magnetic topological phases
• Surface state prediction

Best Practices

• Use fine k-mesh for accurate invariants
• Verify with multiple methods
• Check convergence with mesh density
• Validate against known materials

Community and Support

• CPC publication
• Zenodo data repository
• Academic correspondence

Verification & Sources

Primary sources:

1. Comput. Phys. Commun. (2023), doi:10.1016/j.cpc.2023.108836
2. arXiv: https://arxiv.org/abs/2303.16306
3. Zenodo: Data and code repository

Confidence: VERIFIED - Published in CPC

Verification status: ✅ VERIFIED

• Publication: CPC peer-reviewed
• arXiv preprint: ACCESSIBLE
• Data: Zenodo repository
• Method: Chern/Z2 for WIEN2k