WannSymm

Official Resources

• Homepage: https://github.com/ccao/WannSymm
• GitHub: https://github.com/ccao/WannSymm
• Publication: G.-X. Zhi et al., Comput. Phys. Commun. 271, 108196 (2022)
• License: Check repository

Overview

WannSymm is a symmetry analysis code for Wannier orbitals. It analyzes the symmetry properties of Wannier functions obtained from Wannier90 calculations and can symmetrize tight-binding Hamiltonians to restore exact crystallographic symmetry that may be broken due to numerical errors.

Scientific domain: Wannier functions, symmetry analysis, tight-binding models Target user community: Researchers using Wannier90 for tight-binding model construction

Theoretical Methods

• Symmetry operation analysis on Wannier orbitals
• Point group representation theory
• Tight-binding Hamiltonian symmetrization
• Character table analysis
• Irreducible representation assignment

Capabilities (CRITICAL)

• Symmetry Analysis: Analyze symmetry of Wannier orbitals
• Hamiltonian Symmetrization: Restore exact crystallographic symmetry
• DFT Interface: Works with VASP, WIEN2k, Quantum ESPRESSO
• SOC Support: Handles spin-orbit coupling calculations
• Representation Assignment: Assign irreps to Wannier functions
• Wannier90 Compatible: Direct interface with Wannier90 output

Sources: WannSymm documentation, CPC publication

Key Strengths

Multi-code Support:

• VASP interface
• WIEN2k interface
• Quantum ESPRESSO interface
• Consistent workflow

Symmetrization:

• Fix numerical symmetry breaking
• Improve TB model quality
• Essential for topological analysis
• Better band interpolation

Published Method:

• Peer-reviewed in CPC
• Validated methodology
• Documented algorithms
• Academic support

Inputs & Outputs

• Input formats:

  • Wannier90 output files (wannier90_hr.dat)
  • DFT symmetry information
  • Crystal structure

• Output data types:

  • Symmetrized Hamiltonian
  • Symmetry analysis report
  • Irreducible representations
  • Character tables

Installation

git clone https://github.com/ccao/WannSymm.git
cd WannSymm
# Follow compilation instructions in README

Usage Examples

# Create input file WannSymm.in
# Run WannSymm
./WannSymm.x < WannSymm.in

# Input file example:
DFTcode = 'VASP'
Spinors = F
prefix = 'wannier90'
OutDir = './'

Performance Characteristics

• Speed: Fast symmetry analysis
• Accuracy: Restores exact symmetry
• Reliability: Validated against known systems

Limitations & Known Constraints

• Wannier90 required: Needs Wannier90 calculation first
• Symmetry input: Requires proper symmetry specification
• Learning curve: Understanding symmetry concepts needed

Comparison with Other Tools

• vs symWannier: Different symmetrization approaches
• vs SymClosestWannier: WannSymm post-processing focused
• Unique strength: Symmetry analysis and symmetrization combined

Application Areas

• Topological material studies
• Tight-binding model improvement
• Transport calculations
• Band interpolation
• Symmetry-constrained modeling

Best Practices

• Verify initial Wannier functions quality
• Check symmetry operations match crystal
• Validate symmetrized bands against DFT
• Use for topological invariant calculations

Community and Support

• GitHub repository
• CPC publication
• Academic correspondence

Verification & Sources

Primary sources:

1. GitHub: https://github.com/ccao/WannSymm
2. G.-X. Zhi et al., Comput. Phys. Commun. 271, 108196 (2022)

Confidence: VERIFIED - Published in CPC

Verification status: ✅ VERIFIED

• Official repository: ACCESSIBLE
• Documentation: AVAILABLE
• Source code: OPEN (GitHub)
• Academic citations: CPC publication