Gradual disappearance of the Fermi surface near the metal-insulator transition inLa1−xSrxMnO3thin films

Abstract

We report the observation of changes in the electronic structure of ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}\mathrm{Mn}{\mathrm{O}}_{3}$ (LSMO) across the filling-control metal-insulator (MI) transition by means of in situ angle-resolved photoemission spectroscopy (ARPES) of epitaxial thin films. The Fermi surface gradually disappears near the MI transition by transferring spectral weight from the coherent band near the Fermi level $({E}_{F})$ to the lower Hubbard band, whereas a pseudogap behavior also exists in the ARPES spectra in the close vicinity of ${E}_{F}$ for metallic LSMO. These results indicate that the spectral weight transfer derived from strong electron-electron interaction dominates the gap formation in LSMO associated with the filling-control MI transition.