Anisotropic band evolution of bulk black phosphorus induced by the uniaxial tensile strain

Abstract

Abstract In this study, the anisotropic band structure and its evolution under tensile strains along different crystallographic directions in bulk black phosphorus (BP) have been investigated by angle resolved photoemission spectroscopy (ARPES) and density functional theory (DFT). The results show that there are band crossings in the Z-L (armchair) direction, but not in the Z-A (zigzag) direction. And the corresponding dispersion-k distributions near valence band maximum (VBM) exhibit quasi-linear or quadratic relationships, respectively. Along the armchair direction, the tensile strain expands the interlayer spacing and shifts the VBM to deeper levels with a slope of -16.2 meV/% strain. On the other hand, the tensile strain along the zigzag direction compresses the interlayer spacing and causes the VBM to shift towards shallower levels with a slope of 13.1 meV/% strain. This work demonstrates an effective way of band engineering of bulk BP by uniaxial tensile strain, elucidates the mechanism behind it, and paves the way for strain-regulated optoelectronic devices based on bulk BP.