Dirac fermions in monolayer blue phosphorus: A multi-orbital tight-binding investigation

]This work is a theoretical investigation of the energy dispersion bands of blue phosphorus (buk-P) system within the multi-orbital tight-binding (MOTB) approach. The aim is to corroborate the presence of Dirac fermions, as observed in a recent experimental study. The existence of the Dirac cone at the high-symmetry K point primarily arises from the contributions of elemental phosphorus (P) s, px, and py atomic orbitals. Note that the Fermi velocity of the monolayer buk-P system (vf approximate to 2.2 x 106 m s-1) is approximately 3 times higher than that of graphene (G). This discovery classifies monolayer buk-P as a novel and scarce two-dimensional Dirac material. Furthermore, it has been reported that these Dirac fermions exhibit remarkable adaptability along the Gamma-K region while preserving their degeneracy intact.Here, we quantitatively improve the overall tight-binding (TB) picture of the monolayer buk-P throughout the Brillouin zone (BZ) by engaging more neighboring interacting sites up to the fifth intra-layer nearest-neighbors (5NN). However, our models reproduce the computations based on the DFT approach and the experimental findings quite accurately.To the best of our knowledge, this work is the first to systematically investigate the presence of Dirac cone in monolayer buk-P system within the MOTB model. This rigorous analytical approach, along with the experimental observations and DFT computations, holds significant promise for exploring the intrinsic characteristics of Dirac materials beyond buk-P. Moreover, the observed electronic properties and high Fermi velocity make this material a highly promising candidate for future high-performance nano-electronic devices.