post_wan

This python3 library provides classes for tight-binding calculations with Wannier Hamiltonians, but can be easily applied to general user-defined tight-binding Hamiltonians. The object oriented usage allows for maximal flexibility.

Capabilities

• Calculation of the following expectation values:
  • Polarization calculation of operators L,S,J
  • Expectation value calculation of self-defined k-independent operators
  • Berry curvature and orbital moment of Bloch state
  • Band inversion character
• Winding number/Pontryagin index of 3D expectation values
• Wannier charge center movement
• H(k) Fouriertransformation for w2dynamics input
• ...

Required python modules

• numpy
• scipy
• time
• optional: joblib, multiprocessing

Usage

Please see the examples, a short overview is given below.

hamiltonian class

Allows to import VASP/WANNIER90 created Hamiltonians, provides $H(K)$ and $\nabla H(K)$.

k_space class

Allows to define paths and grids in momentum space. Converts between reduced and cartesian coordinates.

observables class

Main class for calculating k-dependent (BC, BC_OAM) and k-independent (L,S,J) observables. Allows also the usage of user-defined operators.

wcc class

Calculation of the $\mathbb{Z}_2$-invariant from the Wannier Charge Center (WCC) movement. Follows the approach of A. Soluyanov and D. Vanderbilt (https://journals.aps.org/prb/abstract/10.1103/PhysRevB.83.235401).

Contact

philipp.eck@physik.uni-wuerzburg.de