Effect of spin-orbit interaction on the excitonic effects in single-layer, double-layer, and bulk MoS2
Abstract
We present converged ab-initio calculations of the optical absorption spectra of single-layer, bi-layer, and bulk MoS. Both the quasiparticle-energy calculations (on the level of the GW approximation) and the calculation of the absorption spectra (on the level of the Bethe-Salpeter equation) explicitly include spin-orbit coupling, using the full spinorial Kohn-Sham wave-functions as input. Without excitonic effects, the absorption spectra would have the form of a step-function, corresponding to the joint-density of states of a parabolic band-dispersion in 2D. This profile is deformed by a pronounced bound excitonic peak below the continuum onset. The peak is split by spin-orbit interaction in the case of single-layer and (mostly) by inter-layer interaction in the case of double-layer and bulk MoS. The resulting absorption spectra are thus very similar in the three cases but the interpretation of the spectra is different. Differences in the spectra can be seen around 3 eV where the spectra of single and double-layer are dominated by a strongly bound exciton.
Keywords
Cite
@article{arxiv.1306.4257,
title = {Effect of spin-orbit interaction on the excitonic effects in single-layer, double-layer, and bulk MoS2},
author = {Alejandro Molina-Sánchez and Davide Sangalli and Kerstin Hummer and Andrea Marini and Ludger Wirtz},
journal= {arXiv preprint arXiv:1306.4257},
year = {2013}
}