Hexagonal boron phosphide monolayer exfoliation induced by arsenic incorporation in the BP (111) surface: A DFT study

Density functional theory (DFT) calculations have been performed to investigate adsorption and incorporation of arsenic on the boron phosphide (1 1 1) surface. We considered different arsenic coverages. Dimers (1/2 ML), trimers (3/4 ML), and atomic wires (1 ML) are formed upon increasing As coverage. However, at full monolayer, the most relevant result is the hexagonal boron phosphide (h-BP) monolayer formation, a 2D graphene-like structure. The h-BP monolayer phonon dispersion shows only positive frequencies indicating dynamical stabil ity. At the same time, this suggests the possible h-BP monolayer exfoliation (desorption energy of only 0.26 eV/ 1x1) because it is weakly attached to the substrate by van der Waals interactions, as demonstrated by the noncovalent interaction index analysis. Electronic band structures indicate that this 2D layer may support direct transitions, making it useful for applications in electronic devices. The density of states and projected density of states complement the electronic properties analysis. We encourage the experimental realization of h-BP by As incorporation on BP surfaces.

Automated summary

DFT calculations were used to study the adsorption and incorporation of arsenic on the boron phosphide surface, showing the formation of different structures at various arsenic coverages. The most significant result is the formation of a hexagonal boron phosphide monolayer at full coverage, which exhibits positive phonon dispersion and weak attachment to the substrate. The electronic band structures suggest potential direct transitions and applications in electronic devices, supported by density of states analysis.