  In order to investigate the interface termination dependence of perovskite
band alignments, we have studied the Schottky barrier height at
La$_{0.7}$Sr$_{0.3}$MnO$_3$/Nb:SrTiO$_3$ (001) heterointerfaces. As the
Nb:SrTiO$_3$ semiconductor was varied from TiO$_2$ termination to SrO
termination by variable insertion of a SrMnO$_3$ layer, a large systematic
increase in the Schottky barrier height was observed. This can be ascribed to
the evolution of the interface dipole induced to screen the polar discontinuity
at the interface, which gives a large internal degree of freedom for tuning
band diagrams in oxides.
