Published in Phys. Rev. B 80, 075320 (2009).
Influence of surface states on tunneling spectra of n-type
Nobuyuki Ishida,1 Kazuhisa Sueoka,1 and R. M. Feenstra2
1Graduate School of Information Science and Technology,
Hokkaido University, kita-14 Nishi-9, Kita-ku, Sapporo 060-0814, Japan
2Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
We show that surface states within the conduction band of n-type GaAs(110) surfaces play an
important role in reducing the tunneling current out of an accumulation layer that forms due to
an applied potential from a nearby probe tip. Numerical computation of the tunneling current
combined with an electrostatic potential computation of the tip-induced band bending (TIBB)
reveals that occupation of the surface states limits the TIBB, thus leading to the limitation of
the accumulation. As a result, the tunneling current out of the accumulation layer is strongly
suppressed, which is in quantitative agreement with the experiment.
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