Band mapping in the one-step photoemission theory: Multi-Bloch-wave structure of final states and interference effects

A Bloch-waves based one-step theory of photoemission is developed within the augmented plane wave formalism. The multi-Bloch-wave structure of photoelectron initial and final states is found to manifest itself in strong interference of transition amplitudes between their Bloch components. This leads to prominent spectral features with characteristic photon energy dispersion, experimentally found for VSe2 and TiTe2. The Bloch-wave method offers a general band mapping tool indispensable in cases of strong interference and non-free-electron band structure, in which the common direct transitions analysis fails.