Angle-Resolved Photoelectron Spectroscopy Studied Based on Plane Density of States. Application to Beryllium

Intensity of angle-resolved photoelectron spectrum from valence bands of single crystals has been derived. It depends on properties of photon, parameters of crystals and orientation of spectrometer. Information possible from experiment and experimental conditions has been analyzed to simplify the theoretical interpretation. The important influence of the angle of acceptance on the results of X-ray photoelectron spectroscopy is in detail investigated. The plane density of states (PDOS) has been introduced as a new characteristic property of electronic structure describing the angle-resolved photoelectron spectroscopy (ARPES). Application of the derived theory to hexagonal crystal Beryllium (Be) is realized by the calculations and discussions of PDOSs for its ГA, ГM and ГA directions whose results show significant anisotropy. These direction dependences of PDOSs contribute to valuating not only the number but also the energy-independence, energy-dependence, and the other properties of electronic states of the considered material taken from ARPES. The peaks of PDOSs are explained in terms of band structure.

Keywords: Angle-resolved photoelectron spectroscopy, plane density of states, band structure, orientation of crystal and spectrometer dependence, hexagonal crystal Be.