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Abstract

As a continuation of our recent ab initio calculations of
SrTiO3(1 0 0) surface relaxation for the two different
terminations (SrO and TiO2) [Phys. Rev. B 64 (2001) 23417], we
analyze here their electronic structures (band structure,
density of states, and the electronic density redistribution
with emphasis on the covalency effects). We compare results of
ab initio Hartree-Fock method with electron correlation
corrections and density functional theory with different
exchange-correlation functionals, including hybrid (B3PW,
B3LYP) exchange techniques. Our results are also compared with
previous ab initio plane-wave local density approximation
calculations and experiments when available. Considerable
increase of Ti-O chemical bond covalency nearby the surface and
the gap reduction, especially for the TiO2 termination, are
confirmed. (C) 2002 Elsevier Science B.V. All rights reserved.