Using a real-time implementation of the self-consistent GW method, we theoretically investigate the photo-induced changes in the electronic structure of the quasi two-dimensional semi-metal BaNiS2. This material features four Dirac cones in the unit cell and our simulation of the time- and momentum-resolved nonequilibrium spectral function reveals a flattening of the Dirac bands after a photo-doping pulse with a 1.5 eV laser. The simulation results are consistent with the recently reported experimental data on photo-doped BaNiS2 and ZrSiSe, another Dirac semi-metal. A detailed analysis of the numerical data allows us to attribute the nonequilibrium modifications of the Dirac bands to (i) an increased effective temperature after the photo-excitation, which affects the screening properties of the system, and (ii) to nontrivial band shifts in the photo-doped state, which are mainly induced by the Fock term.
@article{arxiv.2106.07008,
title = {Photo-induced Dirac cone flattening in BaNiS$_2$},
author = {Nikolaj Bittner and Denis Golež and Michele Casula and Philipp Werner},
journal= {arXiv preprint arXiv:2106.07008},
year = {2021}
}