Electronic structure of black phosphorus studied by angle-resolved photoemission spectroscopy

Electronic structures of single crystalline black phosphorus were studied by state-of-the-art angle-resolved photoemission spectroscopy (ARPES). Through high resolution photon energy dependence measurements, the band dispersions along out-of-plane and in-plane directions are experimentally determined. The electrons were found to be more localized in the ab plane than is predicted in calculations. Beside the kz-dispersive bulk bands, a surface resonant state is also observed in the momentum space. Our results strongly suggest that more details need to be considered to fully understand the electronic properties of black phosphorus theoretically.