Here we describe an efficient numerical implementation of the Bethe-Salpeter equation to obtain the excitonic spectrum of semiconductors. This is done on the electronic structure calculated either at the simplest tight-binding level or through density funcional theory calculations based on local orbitals. We use a simplified model for the electron-electron interactions which considers atomic orbitals as point-like orbitals and a phenomenological screening. The optical conductivity can then be optionally computed within the Kubo formalism. Our results for paradigmatic two-dimensional materials such as hBN and MoS2, when compared with those of more sophisticated first-principles methods, are excellent and envision a practical use of our implementation beyond the computational limitations of such methods.
@article{arxiv.2307.01572,
title = {Efficient computation of optical excitations in two-dimensional materials with the Xatu code},
author = {Alejandro José Uría-Álvarez and Juan José Esteve-Paredes and Manuel Antonio García-Blázquez and Juan José Palacios},
journal= {arXiv preprint arXiv:2307.01572},
year = {2023}
}