Photoemission and x-ray absorption study of MgC_(1-x)Ni_3

TL;DR

This study uses photoemission and x-ray absorption spectroscopy to analyze the electronic structure of MgC_(1-x)Ni_3, revealing agreement with theoretical band structures but also suppression of predicted van Hove singularities and signs of electron correlation effects.

Contribution

It provides experimental evidence on the electronic structure of MgC_(1-x)Ni_3, highlighting the suppression of van Hove singularities and the importance of electron correlations among Ni 3d electrons.

Findings

Van Hove singularity peak is suppressed near E_F.

Ni core level spectra show satellites with larger energy separation.

Electron correlation effects among Ni 3d electrons are significant.

Abstract

We investigated electronic structure of MgC_(1-x)Ni_3 with photoemission and x-ray absorption spectroscopy. Both results show that overall band structure is in reasonable agreement with band structure calculations including the existence of von Hove singularity (vHs)near E_F. However, we find that the sharp vHs peak theoretically predicted near the E_F is substantially suppressed. As for the Ni core level and absorption spectrum, there exist the satellites of Ni 2p which have a little larger energy separation and reduced intensity compared to the case of Ni-metal. These facts indicate that correlation effects among Ni 3d electrons may be important to understand various physical properties.