Electronic structure of KTiOAsO4: A comparative study by the full potential linearized augmented plane wave method, X-ray emission spectroscopy and X-ray photoelectron spectroscopy

First-principles self-consistent band-structure calculations of potassium titanyl arsenate, KTiOAsO(4) (KTA), have been made using the full potential linearized augmented plane wave (FP-LAPW) method. Total and partial densities of states of the constituent atoms of KTA have been derived. The results obtained show that the valence band of KTA is dominated by contributions of the O 2p-like states, while the Ti 3d-like states are the main contributors into the conduction band of the compound. Additionally, the FP-LAPW calculations have revealed that potassium atoms are highly ionized in KTA. In the present work, the X-ray emission spectroscopy (XES) and X-ray photoelectron spectroscopy (XPS) methods were also employed to investigate experimentally the electronic structure of potassium titanyl arsenate. For the mentioned compound, the XES K Ll, Ti L alpha, As K beta(2) and O K alpha bands reflecting the valence K s-, Ti s,d-, As p- and O p-like states, respectively, were derived and compared on a common energy scale with the XPS valence-band spectrum. A rather good agreement of the experimental XES and XPS results and the theoretical FP-LAPW data for electronic properties of KTA has been obtained in the present paper. (C) 2008 Elsevier B.V. All rights reserved.