Gradual disappearance of the Fermi surface near the metal-insulator transition in La1-xSrxMnO3 thin films

We report the observation of changes in the electronic structure of La1-xSrxMnO3 (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.