X-ray photoemission study of NiS_{2-x}Se_x (x = 0.0 - 1.2)

TL;DR

This study uses x-ray photoemission spectroscopy to analyze how changing Se content in NiS_{2-x}Se_x affects its electronic structure, revealing a transition from insulating to metallic behavior driven by band width changes.

Contribution

It provides a detailed spectroscopic and theoretical analysis of the electronic structure evolution in NiS_{2-x}Se_x with varying Se content, highlighting the role of band width increase.

Findings

On-site Coulomb correlation strength (U) remains unchanged with Se doping.

Band width (W) increases with Se content, leading to a metal-insulator transition.

System transitions from covalent insulator to pd-metallic state.

Abstract

Electronic structure of NiS_{2-x}Se_x system has been investigated for various compositions (x) using x-ray photoemission spectroscopy. An analysis of the core level as well as the valence band spectra of NiS_2 in conjunction with many-body cluster calculations provides a quantitative description of the electronic structure of this compound. With increasing Se content, the on-site Coulomb correlation strength (U) does not change, while the band width W of the system increases, driving the system from a covalent insulating state to a pd-metallic state.