Seminário de Matéria Condensada - 08/06/2017, 11:00, Sala 426 (Torre Nova)

Since the experimental discovery of graphene in 2004, an enormous scientific effort has been employed in the study of this material, which led to the observation of its remarkable properties and potential applications in the near future. This boom also brought attention to a broader range of materials, the so-called 2D materials, which share some similarities to graphene and can form single layers of one up to a few atoms thick. Among them, Black Phosphorus (BP) is a promising candidate for future applications in electronics, especially due to the tuning of its electronic band gap by the number of layers. In a single layer, also known as phosphorene, the P atoms form two staggered chains bonded by sp3 hybridization, while the different layers are bonded by weak Van-der-Waals interactions.

In this work, we employ a tight-binding parametrization based on the Slater Koster model in order to fit the band structures of single-layer, bilayer and bulk black phosphorus obtained from first-principles calculations. We find that our model, which includes 9 or 17 parameters depending on whether overlap is included or not, reproduces quite well the ab-initio band structures over a wide energy range, especially the occupied bands. Hopping and on-site energies are consistent throughout the different systems, which is an indication that our model is suitable for calculations on multilayer black phosphorus and more complex situations in which fi rst-principles calculations become prohibitive, such as disordered systems and heterostructures with a large lattice mismatch. We also discuss the limitations of the model and how the fi t procedure can be improved for a more accurate description of bands in the vicinity of the Fermi energy.