Gradual disappearance of the Fermi surface near the metal-insulator transition in La1-x Srx Mn O3 thin films

We report the observation of changes in the electronic structure of La1-x Srx Mn O3 (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 (EF) to the lower Hubbard band, whereas a pseudogap behavior also exists in the ARPES spectra in the close vicinity of EF 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.