WannSymm: A symmetry analysis code for Wannier orbitals

We derived explicit expressions of symmetry operators on Wannier basis, and implemented these operators in WannSymm software. Based on this implementation, WannSymm can i) symmetrize the real-space Hamiltonian output from Wannier90 code, ii) generate symmetry operators of the little group at a specific k-point, and iii) perform symmetry analysis for Wannier band structure. In general, symmetrized Hamiltonians yield improved results compared with the original ones when they are employed for nodal structure searching, surface Green's function calculations, and other model calculations. Program summary Program Title: WannSymm CPC Library link to program files: https://doi .org /10 .17632 /zgf4p85pwx .1 Licensing provisions: BSD 3-clause Programming language: C External libraries: spglib; BLAS and LAPACK; MPI libraries (optional) Nature of problem: Generate the symmetry operators in Wannier basis; calculate the symmetry eigenvalues and characters; symmetrize the real-space Hamiltonian according to the crystal structure. It deals with nonmagnetic or magnetic systems with or without spin-orbit coupling. For magnetic systems, it can deal with ferromagnetic, commensurate antiferromagnetic long range ordered collinear or non collinear systems with spin-orbit coupling. Solution method: The code requires the real-space Hamiltonian from Wannier projection, the definition of Wannier basis and the crystal structure associated with the defined basis. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The explicit expressions of symmetry operators on Wannier basis are derived and implemented in the WannSymm software, allowing for symmetrization of real-space Hamiltonian, generation of symmetry operators of little group at specific k-point, and symmetry analysis for Wannier band structure. Symmetrized Hamiltonians yield improved results when employed for nodal structure searching, surface Green's function calculations, and other model calculations.