Effect of surface defects and few-atomic steps on the local density of states of the atomically-clean surface of topological insulator Bi2Se3
A. Yu. Dmitriev+*, N. I. Fedotov+*, V. F. Nasretdinova+, S. V. Zaitsev-Zotov+*
*Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
+Kotel'nikov Institute of Radio-engineering and Electronics of the RAS, 125009 Moscow, Russia
Abstract
The results of ultra-high vacuum low-temperature scanning-tunneling microscopy
(STM) and spectroscopy (STS) of atomically clean (111) surface of the
topological insulator Bi2Se3 are presented. We observed several types of
new subsurface defects whose location and charge correspond to p-type conduction
of grown crystals. The sign of the thermoelectric effect also indicates p-type
conduction. STM and STS measurements demonstrate that the chemical potential is
always located inside the bulk band gap.
We also observed changes in the local density of states in the vicinity of the
quintuple layer steps at the studied surface. This changes correspond either to
the shift of the Dirac cone position or to the shift of the chemical potential
near the step edge.