1. "Grafeno : Prêmio Nobel em Física de 2010 e Perspectivas Tecnológicas“
20/04/2011
"Grafeno : Prêmio Nobel em Física de 2010 e Perspectivas Tecnológicas“
Yakov Kopelevich
Instituto de Física "Gleb Wataghin", UNICAMP

2. Nobel Prize in Physics 2010 – GRAPHENE (Andrei Geim & Konstantin Novoselov). According to the Oficial Web Site of the Nobel Prize (Nobelprize.org) this Prize has been awarded for “groundbreaking experiments regarding the two-dimensional material graphene”.

3. Carbon allotropes

4. Why graphene ?
What are the “groundbreaking
experiments” regarding
this material ?

5. Has graphene been experimentally obtained first in 2004 ?
Actually, prior observations of graphene date back to at least 1962.
H. P. Boehm et al. Zeitschrift für Naturforschung B 17, 150 (1962).
(TEM)

6. EXPERIMENTS on GRAPHENE:
1992
1997

7. 2000
2001

8. HOPG = Highly Oriented Pyrolitic Graphite
FLG
c-axis
With AFM tip:
Xuekun Lu, Minfeng Yu, Hui Huang and Rodney S Ruoff
Nanotechnology , 1999

10. The crystal structure of graphite: layers of honeycomb lattices of
carbon atoms
d = B A
The single-atom thick graphitic plane is called "graphene"
Dirac-like cone spectrum:
E(p) =  vp; v ~ t||a/ћ, v  106 m/s F
Band structure of
one graphitic layer
K - Fermi point

11. Quantum Hall Effect
Klaus von Klitzing

12. Quantum oscillations and/or Quantum Hall Effect (QHE) originate from Landau quantization
> kBT
Lev Landau
B = 0
c > 1
or c << 1
Energy spectra
En = ћc(n + 1/2), c = eB/m*

13. Quantum Hall Array Resistance Standards

14. Quantum effects at room temperature !

15. ?!
 ~ 104 cm2/Vs <<
 ~ 106 cm2/Vs (graphite)

16. Room-Temperature Quantum Oscillations in Bulk Graphite: More Experimental Evidence for Dirac-like Spectrum
HOPG
En = ±(2evF2|n|B)1/2
 ~ 106 cm2/Vs !
Y. Kopelevich and P. Esquinazi, Advanced Materials 19, 4559 (2007)

17. Andre Geim, Nobel Lecture 2010

18. Finding of the Quantum Hall Effect in Graphite
Y. Kopelevich et al., PRL 90, (2003); PRB 68, (2003).
c/basal  105

19. The occurrence of QHE in graphite has been confirmed by others:
QHE measured for 8 m thick
HOPG sample at T = 0.3 K;
K. S. Novoselov et al.,
cond-mat/
QHE measured for a few-layer thick
graphite sample at T = 3 K;
K. S. Novoselov et al., Science’2004

20. Y. Kopelevich et al., PRL 2003
FLG
Novoselov et al., 2004

21. Dirac fermions in graphene and bulk graphite

24. Bulk
graphite

25. Massive electrons Quasi-2D Dirac holes o – max xx (n)
I. A. Luk’yanchuk and Y. K. , PRL 93, (2004); ibid. 97, (2006)
o – max xx (n)
x - min xx (n + 1/2); shifted by 1/2 to the left
Massive electrons
Quasi-2D Dirac holes

26. Hence, before graphene has been measured, its fundamental properties have already been experimentally uncovered.

27. In graphite !
Phys. Rev. Lett. 103, (2009)
Cyclotron resonance measurements on natural graphite

28. spintronics

30. One example:
EPFL

31. “Future of graphene”: