Selective orbital imaging of excited states with x-ray spectroscopy: the example of $\alpha$-MnS

TL;DR

This paper demonstrates that non-resonant inelastic x-ray scattering with an s core level can effectively image and identify excited states and their orbital characters in transition metal compounds, exemplified by $ extalpha$-MnS.

Contribution

It introduces a method using s core level x-ray scattering to selectively image excited states and determine their orbital character in transition metal compounds.

Findings

Successfully imaged excited states of $ extalpha$-MnS

Identified orbital characters as $t_{2g}$ and $e_g$

Measured energy splitting $10Dq$ as 0.78 eV

Abstract

Herein we show that non-resonant inelastic x-ray scattering involving an $s$ core level is a powerful spectroscopic method to characterize the excited states of transition metal compounds. The spherical charge distribution of the $s$ core hole allows the orientational dependence of the intensities of the various spectral features to produce a spatial charge image of the associated multiplet states in a straightforward manner, thereby facilitating the identification of their orbital character. In addition, the $s$ core hole does not add an extra orbital angular momentum component to the multiplet structure so that the well-established Sugano-Tanabe-Kamimura diagrams can be used for the analysis of the spectra. For $\alpha$-MnS we observe the spherical charge density corresponding to its high spin $3d^5$ ($^6A_1$) ground state configuration and we were able to selectively image its excited states and identify them as $t_{2g}$ ($^5T_2$) and $e_g$ ($^5E$) with an energy splitting $10Dq$ of 0.78\,eV.