文档介绍：Spectroscopy of Electrons and Phonons in
Graphene Structures
Inelastic Light Scattering
elementary excitation modes are seen
directly in the spectra
2D electron gas in a GaAs quantum well
B = T T LaserS line
T B 1
ωL - ωS = ω T = K
ω
kL - kS = k ν= c
ω[meV]
k = (2ω/c)sinθ L
L
ω
Intensity
ωL ω
S
kL
k Intensity [.] Energy
S
17 18
Scattered Energy light Shift line [meV]
Spectroscopy of Electrons and Phonons in
Graphene Structures
Why inelastic light scattering
studies in graphene?
Raman scattering (optical phonons):
insights on physics of carbon-based structures
Inelastic light scattering (electrons and holes):
spin or charge excitations of Dirac fermions
Spectroscopy of Electrons and Phonons in
Graphene Structures
Recent Raman studies of single-layer graphene:
• Electric-field effect
• Electron-phonon coupling
Future light scattering studies in graphene:
• Dirac fermion excitations
• Graphene hetero-layers
Spectroscopy of Electrons in
Low-Dimensional Structures
Support from
W. M. Keck Foundation
Office of Naval Research
Columbia NSEC (NSF, NYSTAR)
National Science Foundation
(DMR 03-52738)
Department of Energy
(DE-AIO2-04ER46133 )
Electric-Field-Effect in Graphene
Single layer graphene device Single atomic layer of
carbons
in a b lattice!
Dirac point
5000
4000
< 1 nm
3000
(W)
. Novoselov et al Science 306, 666 (2004) xx
2000
Yuanbo Zhang et al Phys. Rev. Lett 94, 176803 (2005) R
. Novoselov et al Nature 438, 197 (2005)
Yuanbo Zhang et al Nature 438, 201 (2005)
1000 10 nm
0
-80 -60 -40 -20 0 20 40 60 80
Vg (V)
Electric-Field-Effect in Graphene
Single layer graphene device Single atomic layer of
carbons
in a b lattice!
15 6
oresistance (k
) 1 ____ h
2
Ω 2 e
10 4
__1 __h
5 6 e2 2
. Novoselov et al Science 306, 666 (2004) 1 ____ h
2
Yuanbo Zhang et al Phys. Re