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

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.