In situphotoemission study ofNd1−xSrxMnO3epitaxial thin films

Abstract

We have performed an in situ photoemission study of ${\text{Nd}}_{1\ensuremath{-}x}{\text{Sr}}_{x}{\text{MnO}}_{3}$ (NSMO) thin films grown on ${\text{SrTiO}}_{3}$ (001) substrates by laser molecular-beam epitaxy. The lattice constants of the thin films were relaxed from those of the substrates, and the transport properties were almost the same as those of bulk NSMO. From core-level photoemission studies, we found that the behavior of the chemical-potential shift was not much different from that of the bulk NSMO samples. In the valence-band spectra, finite intensity at the Fermi level was observed even in the insulating phase. The band dispersions of ${\text{Nd}}_{0.6}{\text{Sr}}_{0.4}{\text{MnO}}_{3}$ obtained by angle-resolved photoemission spectroscopy were almost the same as those of ${\text{La}}_{0.6}{\text{Sr}}_{0.4}{\text{MnO}}_{3}$ thin films. These results showed that NSMO is closely related to ${\text{La}}_{1\ensuremath{-}x}{\text{Sr}}_{x}{\text{MnO}}_{3}$ in terms of the band structure, except for a decrease in the coherent spectral weight.