Doping and Bond Length Contributions to Mn K-EDGE Shift in La1-xSrxMnO3 and Their Correlation with Electrical Transport Behaviour

摘要

The experimental Mn K-edge x-ray absorption spectra of La1-xSrxMnO3, 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 4p-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 LaMnO3. Such separation is helpful to find the localization behaviour of charge carriers and to understand the observed transport properties and type of charge carrier participating in the conduction process in these compounds.