By performing \emph{ab initio} calculations for one- to four-layer black phosphorus within the GW approximation, we obtain a significant difference in the band gap (∼1.5 eV), which is in line with recent experimental data. The results are analyzed in terms of the constructed four-band tight-binding model, which gives accurate descriptions of the mono- and bilayer band structure near the band gap, and reveal an important role of the interlayer hoppings, which are largely responsible for the obtained gap difference.
@article{arxiv.1404.0618,
title = {Quasiparticle band structure and tight-binding model for single- and bilayer black phosphorus},
author = {Alexander N. Rudenko and Mikhail I. Katsnelson},
journal= {arXiv preprint arXiv:1404.0618},
year = {2014}
}