  Quasiparticle calculations are performed to investigate the electronic band
structures of various polymorphs of Hf and Zr oxides. The corrections with
respect to density-functional-theory results are found to depend only weakly on
the crystal structure. Based on these bulk calculations as well as those for
bulk Si, the effect of quasiparticle corrections is also investigated for the
band offsets at the interface between these oxides and Si assuming that the
lineup of the potential at the interface is reproduced correctly within
density-functional theory. On the one hand, the valence band offsets are
practically unchanged with a correction of a few tenths of eV. On the other
hand, conduction band offsets are raised by 1.3--1.5 eV. When applied to
existing calculations for the offsets at the density-functional-theory level,
our quasiparticle corrections provide results in good agreement with the
experiment.
