Bulk and Surface Electronic Structure of the Weyl-Semimetal TaP

The transition metal monopnictide Tantalum Phosphide, TaP, is a prototypical Weyl semimetal. We examined the electronic band structure of TaP(001) using angle-resolved photoemission spectroscopy (ARPES) within a broad range of excitation energies from the VUV regime to the soft X-ray regime. Utilizing the different probing depths depending on photon energy, we deconvolve surface and bulk contributions to the electronic structure. Based on a comparison to first-principles calculations we identify genuine surface and bulk states, as well as surface resonance states, originating from the hybridization between surface and bulk. We show that the surface resonances display a considerably higher bulk penetration than the pure surface states. Based on our detailed analysis of the character of the electronic states, we discuss the topological properties of the surface band structure.