Electronic band structure of rhombohedral arsenic studied by highly-angle-resolved ultraviolet photoelectron spectroscopy

Angle-resolved ultraviolet photoemission spectra of a rhombohedral arsenic single crystal have been measured for the first time in very high angular resolution with the He i resonance line as an exciting source. The experimentally derived band structure has been compared in detail to the self-consistent pseudopotential calculation performed in this study and with four others presented mainly by Falicov and co-workers. The present angle-resolved photoemission measurement directly identified the location of an electron pocket at the $L$ point in the Brillouin zone and a hole pocket near the $T$ point. It has also been elucidated that contrary to the early calculations only one band goes across the Fermi level near the $L$ point, forming the electron pocket. Some special points with high symmetry and/or almost no dispersion along the interlayer direction have been successfully assigned in the experimentally determined band structure.