  We have performed angle-resolved photoemission spectroscopy on a
heterostructure consisting of topological insulator Bi2Te3 and iron
chalcogenide FeTe fabricated on SrTiO3 substrate by molecular-beam-epitaxy
technique. This system was recently found to show superconductivity albeit
non-superconducting nature of each constituent material. Upon interfacing FeTe
with two quintuple layers of Bi2Te3, we found that the Dirac-cone surface state
of Bi2Te3 is shifted toward higher binding energy, while the holelike band at
the Fermi level originating from FeTe moves toward lower binding energy. This
suggests that electron charge transfer takes place from FeTe to Bi2Te3 through
the interface. The present result points to importance of hole-doped FeTe
interface for the occurrence of unconventional superconductivity.
