  Core-level electronic structure of La1-xSrxMnO3 has been studied by x-ray
photoemission spectroscopy (XPS). We first report, by the conventional XPS, the
well-screened shoulder structure in Mn 2p3/2 peak, which had been observed only
by hard x-ray photoemission spectroscopy so far. Multiple-peak analysis
revealed that the Mn4+ spectral weight was not proportional to the nominal hole
concentration x, indicating that a simple Mn3+/Mn4+ intensity ratio analysis
may result in a wrong quantitative elemental analysis. Considerable weight of
the shoulder at x=0.0 and the fact that the shoulder weight was even slightly
going down from x=0.2 to 0.4 were not compatible with the idea that this weight
simply represents the metallic behavior. Further analysis found that the whole
Mn 2p3/2 peak can be decomposed into four portions, the Mn4+, the (nominal)
Mn3+, the shoulder, and the other spectral weight located almost at the Mn3+
location. We concluded that this weight represents the well-screened final
state at Mn4+ sites, whereas the shoulder is known as that of the Mn3+ states.
We found that the sum of these two spectral weight has an empirical
relationship to the conductivity evolution with x.
