The electronic structure of Pb₂MoO₅: First-principles DFT calculations and X-ray spectroscopy measurements

Highlights: • The Pb₂MoO₅ single crystal was obtained by the LTG Cz technique. • The electronic structure of Pb₂MoO₅ was explored by XPS and XES. • The Pb₂MoO₅(20$\bar{1}$) cleaved surface is stable in reference to the 3.0 keV Ar⁺ ion-irradiation. • The band structure of Pb₂MoO₅ was obtained employing the FP-LAPW method. • The O 2p states contribute predominantly at the top and in the central portions of the valence band. The electronic structure of lanarkite-type Pb₂MoO₅ was explored by experimental and theoretical methods. The XPS and XES measurements were carried out at the cleaved atomic-smooth (20$\bar{1}$) surface prepared from the Pb₂MoO₅ crystal grown by the LTG Cz technique. The ab initio calculations of total and partial densities of states of the atoms constituting Pb₂MoO₅ were obtained employing the full potential linearized augmented plane wave (FP-LAPW) method. The principal contributors to the valence band of Pb₂MoO₅ are the O 2p states which contribute predominantly at the top and in the central portions of the valence band. The Pb 6s and Mo 4d states are among other principal contributors: their main contributions occur at the bottom and in the central portion of the valence band, respectively. Our FP-LAPW data reveal that the Pb₂MoO₅ compound is an indirect-gap material: the valence band maximum and conduction band minimum occur at the X and M points, respectively. The XPS core-level and valence-band spectra were measured for pristine and Ar⁺ ion-irradiated Pb₂MoO₅(20$\bar{1}$) surfaces and the measurements reveal high chemical stability of the Pb₂MoO₅(20$\bar{1}$) cleaved surface in reference to the 3.0 keV Ar⁺ ion-irradiation.