List of records in nano database
IDs:
112
Authors : |
Márk,Géza,I.;Biró,László,P.;Gyulai,József;Thiry,Paul,A.;Lucas,Amand,A.;Lambin,Philippe |
Title : |
Simulation of scanning tunneling spectroscopy
of supported carbon nanotubes |
JournalName : |
Phys.Rev.B |
PubDateYear : |
2000 |
PubDateOther : |
15 July |
Volume : |
62 |
Issue : |
4 |
StartPage : |
2797 |
EndPage : |
2805 |
Keywords : |
|
Notes : |
|
Abstract : |
The angle and energy dependent transmission of
wave packets was calculated through a jellium
potential model of a scanning tunneling microscope
(STM) junction containing different arrangements
of carbon nanotubes. The total tunnel current
as a function of STM bias was calculated by
statistical averaging over a distribution of
wave packets in the allowed energy window.
Three tunneling situations were studied:
(i) a STM tunnel junction with no nanotube
present, (ii) one single wall nanotube in the STM
junction, and (iii) a nanotube "raft."
The effects of point contacts at the STM
tip/nanotube, at the nanotube/substrate,
and at both interfaces were also investigated.
The theory allowed us to identify components
of pure geometrical origin responsible for the
asymmetry in the scanning tunneling spectroscopy
(STS) spectrum of the carbon nanotubes with
respect to bias voltage polarity.
The calculations show that for tip negative bias
the angular dependence of the transmission
is determined by the tip shape. The particular
tip shape introduces an asymmetry on the negative
side of the STS spectrum. For tip positive bias
the angular dependence of the transmission
depends strongly on the nature of the nanosystem
in the STM gap. While the transmission of the
STM tunnel junction with no nanotube present
can be well represented by a one dimensional
model, all other geometries cause a large
normal-transverse momentum mixing of the
wave packet. A diffraction-grating-like behavior
is seen in the angular dependence of the
transmission of the nanotube raft. Point contacts
between the nanotube and the substrate cause
an asymmetry in the positive side of the STS
spectrum. Calculated STS spectra are compared
to experimental ones. |
HTML_Local : |
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HTML_Remote : |
http://ojps.aip.org/journal_cgi/getabs?KEY=PRBMDO&cvips=PRBMDO000062000004002797000001&gifs=Yes |
Preprint_Local : |
http://www.nanotechnology.hu/reprint/prb_62_2797.pdf |
Preprint_Remote : |
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