Temperature-dependent valence-band photoemission spectra of ${\mathrm{La}}_{1-x}$${\mathrm{Sr}}_x$MnO${}_3$

We have studied the temperature dependence of the photoemission spectra of La${}_{1-x}$Sr${}_x$MnO${}_3$ $(x$=0.0, 0.2, and 0.4) and found that the spectral line shape dramatically changes in the entire valence-band region, particularly for $x$=0.2 and 0.4. By contrast, the spectra of La${}_{0.6}$Sr${}_{0.4}$CoO${}_3$ show no significant temperature dependence. From comparison between the temperature- and composition-$\mathrm{}\left(x\right)\mathrm{}$ dependent spectral changes and the temperature-composition phase diagram of La${}_{1-x}$Sr${}_x$MnO${}_3$, we suggest that the changes are related to the degree of hole localization on oxygen $p$ orbitals, which is influenced by electron-lattice coupling and magnetic correlations.