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Andre Geim (1958) is a Russian-born Dutch physicist,currently director of the Manchester Centre forMesoscience and Nanotechnology at the ManchesterUniversity, known for the discovery of graphene, thedevelopment of gecko tape and demonstrations ofdiamagnetic levitation.
Konstantin Sergeevich Novoselov (1974) is a Russian-British physicist, currently Professor at the University ofManchester, known for his work on mesoscopicsuperconductivity , Sub-atomic movements of magneticdomain walls, the invention of graphene.
Nobel prize in physics 2010
Recent progress on graphene
Reza [email protected]
11The annual spring conference , IPM 19-20 May 2011
33
1. Introductionbrief overview ( Experimental & Theoretical views)
2. New resultsStrain ( engineering) in grapheneOptical propertiesElectron-electron interaction
3. ConclusionSpecial characteristic…..Open problems
Outlook
44
Graphite and Pencil
:روش ساخت Micromechanical cleavage
Epitaxy, requires ultrahigh vacuum conditions: Expensive Science 312, 1192 (2006)Various chemical methods. Nano Lett. 8, 2442 (2008) , Nature Nanotech. 3, 270 (2008);ibid 4,217(2009)Chemical Vapour Deposition : Nature 457, 706 (2009), Nano Lett. 9, 30 (2009)
Geim’s group: Science 306, 666 (2004) , Nature 438, 197(2005)
55
66
Graphene preparations
A. Geim Science 324, 1530(2009)
77
Graphene preparations
Keun Soo Kim, et al, Nature 457, 706(2009)
88
New preparations
Sukang Bae, et al, Nature nanotechnology 5, 574(2010)
99
Graphene as a Touch-Screen
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Samsung @ SKKU project
Flexible display in a large scale graphene based material
1111
Basic concepts in graphene
• Flatness, one atom thickness• Crystal structure• Dispersion relation• Chirality
Graphene has twoatoms per unit cell.
These two atoms fortwo interlockingtriangular sub-lattices.
- A atom
- B atom
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Graphene, a honeycomb lattice
Flat monolayer: roughness, ripples, wrinkles?
1313A. Geim Science 324, 1530(2009)
dispersion relations & chirality
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“Imagine a piece of paper but a million times thinner. This ishow thick graphene is.
Imagine a material stronger than diamond. This is how stronggraphene is [in the plane].
Imagine a material more conducting than copper. This is howconductive graphene is.
concerns new physics, no one doubts about it already...‘‘ …..
What graphene is?
nm *
qE
Novoselov, et al., Nature 438,197 (2005)
nq
Dirac massless: evidence
1515
1616
How do we determine the Fermi surface?
Angle-resolved photoemissionspectroscopy (ARPES)
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Some applications
• Klein tunneling• Transistors• Thermal conductivity• High mobility• Quantum dots• Strain engineering•Tunable gap in bilayer• Photonic and Solar cell• …..
1818
Observation of Klein tunneling
Williams, Di Carlo and Marcus, Science 317, 638(2007)
Satnder, Huard and Goldhaber-Gordon, Phys. Rev. Lett. 102, 026807 (2009)
1919Lin et al., Science. 327, 662 (2010)
100-GHz Transistors
2020Liao, et al., Nature In press (2010)
High-speed graphene transistors
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Graphene spreads the heat
Suspended SLGSupported SLG by Sio2Bulk copperThin film copper
1 13000 5000 Wm k 1 1600 Wm k
1 1400 Wm k
1 1250 Wm k
Seol, et al., Science 328, 213(2010)
At room temperature :
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Quantum dots in graphene as a basic forelectronic devices
Ponomarenko, et al., Science 320, 356 (2008)
2323
Strain Enginnering
Elasticity Theory Quantum mechanics
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1t
2t3t
ij jiij batH
Deformed graphene lattice
02 uua
ttt ijijij
)()(0 ruuu ijij
2525
IVeAPvH F )(
Graphene is distorted, the effective Hamiltonian will be changed into
Effective Hamiltonian
H. Suzuura and T. Ando, Phys. Rev. B 65, 235412 (2002)J. L. Manes, Phys. Rev. B 76, 045430 (2007)
VveAPeAPVv
vPHF
FF 1
**1
)(
VveAPeApVv
vpHF
FF 1**
1
)(
yx iAAA
2626
Induced vector potential field is defined through the deformations of sample
Strains:
0.56
K.V. Zakharchenko, M.I. Katsnelson, and A. Fasolino, Phys. Rev. Lett. 102, 046808 (2009)Y. C. Cheng, Z. Y. Zhu, G. S. Huang, and U. Schwingenschlögl, Phys. Rev. B 83, 115449 (2011)
Strains
2)()( aLogtLog
hhuuu 2
xyyF
yyxxxF
utAev
uutAev
23
)(4
3
2727
Elasticity theory
Pseudo-magnetic field
Deformed lattice
Ideas
2828
Effective Hamiltonian
F. Guinea, B. Horovitz and P. Le Doussal, Phys. Rev. B 77,205421(2008)E. V. Castro, et al. Phys. Rev. Lett. 105, 266601 (2010).Tony Low and F. Guinea, Nano Lett. 10, 3551 (2010).Vitor M. Pereira and A. H. Castro Neto, Phys. Rev. Lett. 103, 046801 (2009)
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Experiment
Leavy et al. Science 329, 554 (2010)
3030
Exp vs Theory
Leavy et al. Science 329, 554 (2010)
3131
Numerical Results vs Experiment data
N. Abedpour, R. A., F. Guinea , to be submitted
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Graphene ring: analytical solutions
Landau and Lifshitz, Theory of Elasticity, (Harvard)
0),( rh
0),(),(
0),(),( 11
RuURu
RuRu
r
r
21
221
2
21
)(),(
0),(
RRrR
RRrRRUru
rur
N. Abedpour, R. A., F. Guinea , submitted
3333
Analytical solutions: Pseudo-magnetic field
TnmRB 10)19,10( 01
example:
3
214
1 1056.0),,(rRRrB
)3cos()(
34),( 21
23
21
0
RRrRRU
arB
eh20
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Numerical results
)3cos(),( rBN. Abedpour, R. A., F. Guinea , submitted
3535
Co-exist CQHE with TRI ?
A. Vaezi, N. Abedpour, R. A., To be submitted
3636
Optical transmission propeties
Nearly perfect transparent
3737
Transmission of SLG/SiO2/Si
C. Lee et al., Appl. Phys. Lett. 98, 071905 (2011)
3838
Many-body effects
Are the many-body electron- electron interactionsessential for graphene?
X. Du, I. Skachko, F. Duerr, A. Luican, and E.Y. Andrei, Nature 462, 192 (2009)
K.I. Bolotin, F. Ghahari, M.D. Shulman, H.L. Stormer, and P. Kim, Nature462, 196 (2009)
Fractional quantum Hall effect
Interaction effects in STM
V.W. Brar et al., Phys. Rev. Lett. 104, 036805 (2010)
4141
ARPES: Gapless graphene
M. Polini, R. Asgari, G. Borghi, Y. Barlas, T. Pereg-Barnea, and A.H. MacDonald, Phys. Rev. B 77,081411(R) (2008)
4242
A. Qaiumzadeh and R. Asgari,New J. Physics, 11, 095023 (2009)
ARPES: gap opening
The plasmaron peak is suppressed
4343
Our recent work Science 328,999(2010)
4444
Dispersion relation (experiment)
4545Non-interacting,single-particle picture
Interacting,many-particles picture
My purpose
4646
Graphene on Metal
A. Principi, R. A, M. Polini, Submitted
4747
Phase diagram
A. Principi, R. A, M. Polini, Submitted
4848
Soundaron
A. Principi, R. A, M. Polini, Submitted
4949
Conclusion
1. Composite “ Plasmaron “ particles were observed.2. A quantitative agreement between experimental measurements
and theoretical model is satisfied.3. Dirac crossing is resolved into three crossing.4. Plasmaron properties can be used in photonic and electronic devices.
5050
Open problems
1. Quantum update ( see: San-Jose, Gonzalez and Guinea, arXiv:1009.1285)2. Chemical properties3. Transport properties near to the Dirac point4. More applications in PHOTONIC and SOLAR CELL5. Electronic properties ( the impact of e-e and e-ph interactions)6. Gas Sensors7. Nonlinear mechanical properties
5151
Allan MacDonald
Marco Polini
Eli RotenbergAaron BostwickThomas SeyllerKaron Horn
Experimentalists
Theorists
In collaborations with
Floran Speck
NimaAlireza
Khadijeh
reza
Ayub
Paco Guinea
H Cheraghchi
Ali Naji
H Vaezi
Thanks for your attention
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