Doping and bond length contributions to Mn K-edge shift in La$_{1-x}$Sr$_x$MnO$_{3}$ and their correlation with electrical transport properties

TL;DR

This study investigates how doping and bond length changes influence the Mn K-edge shift in La$_{1-x}$Sr$_x$MnO$_{3}$ and correlates these effects with the material's electrical transport properties using experimental spectra and band structure calculations.

Contribution

It introduces a method to distinguish doping and bond length effects on Mn K-edge shifts, enhancing understanding of charge localization and transport in these materials.

Findings

Edge shift correlates with unoccupied Mn 4p-band center.

Separation of doping and bond length effects elucidates charge localization.

Results link structural changes to electrical transport behavior.

Abstract

The experimental Mn K-edge x-ray absorption spectra of La$_{1-x}$Sr$_x$MnO$_{3}$, $x$ = 0 - 0.7 are compared with the band structure calculations using spin polarized density functional theory. It is explicitly shown that there is a correspondence between the inflection point on the absorption edge and the centre of gravity of the unoccupied Mn 4$p$-band. This correspondence has been used to separate the doping and size contributions to edge shift due to variation in number of electrons in valence band and Mn-O bond lengths, respectively when Sr is doped into LaMnO$_3$. Such separation is helpful to find the localization behaviour of charge carriers and to understand the observed transport properties of these compounds.