Electronic properties of Zr4M2O (M = Fe, Co, Ni) intermetallic compounds: first-principles APW+LO calculations and X-ray photoelectron spectroscopy data

 

Chem. Met. Alloys 6 (2013) 150-157

 

A.A. LAVRENTYEV, B.V. GABRELIAN, P.N. SHKUMAT, E.I. KOPYLOVA, I.Y. NIKIFOROV, I.Y. ZAVALIY, A.K. SINELNICHENKO, O.Y. KHYZHUN

 

First-principles band-structure augmented plane wave + local orbitals (APW+LO) calculations as incorporated in the WIEN2k code, as well as X-ray photoelectron spectroscopy (XPS) measurements, were performed to elucidate the electronic structure of the Zr4M2O (M = Fe, Co, Ni) oxides, very prospective hydrogen-storage materials. Total and partial densities of states for the oxides were derived from the APW+LO calculations. Our calculations show that the O 2p states make the major contributions at the bottom of the valence band, while the M 3d and Zr 4d states are the dominant contributors at the top of the valence band and at the bottom of the conduction band. Peculiarities of the occupation of the valence band predicted by the APW+LO calculations for Zr4Fe2O are confirmed experimentally by comparison on a common energy scale of the XPS valence-band spectrum and the curve of total DOS.

 

Crystal structure of Zr4Fe2O: O  small circles, Fe  medium circles, Zr  large circles.

 

Keywords

Alloys / Intermetallic compounds / First-principles calculations / X-ray photoelectron spectroscopy / Electronic structure