ARPES studies in LaTiO3/SrTiO3 heterostructures*

Electronic band structure of LaTiO3/SrTiO3 heterostructures was studied using angle resolved photoemission spectroscopy (ARPES). LaTiO3 films, grown by in situ pulsed laser deposition (PLD) on beamline 7.0.1 at Advanced Light Source, exhibit a thickness-dependent phase transition from the correlated metallic interface to Mott insulator. We observed the quasi-particle peak at the Fermi level explaining the metallic interface for ultrathin LaTiO3, and the band gap opened for thick LaTiO3 similar to the bulk. We compare the thickness dependent electronic structure with theoretically calculated phase diagram (S. Okamoto and A. J. Millis, Nature 428, 630 (2004)).