Transcript Electron Transport in Carbon Nanotubes

Electron Transport in Carbon
Nanotubes
Shaun Ard
Physics 672
Nanotubes: Basics

Composed of “rolled up”
graphene sheets

Singly and Multi-walled
varieties

Kohlenstoffnanoroehre Animation
Copyright Alain Rochefort
Fully characterized by
the chiral vector
–
C h = n â 1 + m â2
A. Maiti, Caron Nanotubes: Band gap engineering
with strain, Nature Materials 2 (2003) 440
Electronic Properties: Theory

1-D band structure
calculated from 2-D
graphene band structure
using “zone folding” scheme

Ekμ= E2D(k*K2/|K2|+μK1)
–
K1=(-t2b1+ t1b2)/ N
–
K2=(mb1- nb2)/ N
(5,5)
(9,0)
(10,0)
V. Popov, Carbon nanotubes: properties and applications,
Materials Science and Engineering R 43 (2004) 61-102
Scanning Tunneling Microscopy
(STM)

Scanning Tunneling
Microscopy (STM)
capable to probe both
structure and electronic
density of states
simultaneously.

Evidence of both semiconducting and metallic
behavior based on (n,m)
index.
T.W. Odomet al, Atomic Structure and
Electronic Properties of Single-Walled
Nanotubes, Nature (London) 391 (1998) 62
Nanotube Contacts: Bulk and
End Connected
Coulomb blockade
M. Bockrath, D. Cobden, P. McEuen, N. Chopra, A. Zettl, A. Thess,
R. E. Smalley, Single-Electron Transport in Ropes of Carbon
Nanotubes , Science 275 (1997) 1922
Coulomb Blockade Only?
M. Bockrath, D. Cobden, Jia Lu, A. Rinzler, R.
Smalley, L. Balents, P. McEuen, Luttinger-liquid
behaviour in carbon nanotubes, Nature 397 (1999)
598
Luttinger Liquid Behavior?
M. Bockrath, D. Cobden, Jia Lu, A. Rinzler, R. Smalley, L.
Balents, P. McEuen, Luttinger-liquid behaviour in carbon
nanotubes, Nature 397 (1999) 598
Even More Exotic Physics
B. Babic and C. Schönenberger, Observation of Fano resonances in
single-wall carbon nanotubes, Phys. Rev. B 70 (2004) 195408
Fano Resonances
B. Babic and C. Schönenberger, Observation of Fano resonances in
single-wall carbon nanotubes, Phys. Rev. B 70 (2004) 195408
Frequency Dependant Studies
Frequency Dependant Studies cont.
Many Areas of Current and
Continued Study

Composite structures
–

Crossed junctions
–

S. Shi et al., Electronic transport properties of multiwall carbon
nanotubes/yttria-stabilized zirconia composites, J. Appl. Phys. 101,
(2007) 023708
J. Park et al., Electrical transport through crossed carbon nanotube
junctions, J. Appl. Phys. 93, (2003) 4191
Aharonov–Bohm effect
–
A. Bachtold et al., Aharonov–Bohm oscillations in carbon nanotubes,
Nature 397 (1999), 673