Band structure of a ribbon

The following script shows how to generate a ribbon of a given material, i.e. how to reduce the dimensionality of the system along one specified direction, and obtain the bands of the new system. Note that here, for Bi(111) which has a honeycomb lattice, the generated ribbon is not rectangular but has diamond shape. To generate a rectangular ribbon, one can use instead the method tightbinder.system.System.ribbon(), which is specific to honeycomb lattices.

bands_ribbon_bi111.py

from tightbinder.models import SlaterKoster
from tightbinder.fileparse import parse_config_file
import matplotlib.pyplot as plt
from pathlib import Path

def main():

    # Parse configuration file
    path = Path(__file__).parent / ".." / "examples" / "inputs" / "Bi111.yaml"
    config = parse_config_file(path)

    # Init. model and consider a finite supercell along one Bravais vector
    width = 15
    model = SlaterKoster(config).reduce(n1=width)

    # Create k point mesh
    nk = 100
    labels = ["K", "G", "K"]
    kpoints = model.high_symmetry_path(nk, labels)

    # Initialize Bloch Hamiltonian and obtain the band structure
    model.initialize_hamiltonian()
    results = model.solve(kpoints)

    # Plot bands of the ribbon; restrict energy window to [-2, 2] interval.
    results.plot_along_path(labels, e_values=[-2, 2])


if __name__ == "__main__":
    main()
    plt.show()

Executing this script results in the following plot: