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Adatoms in Graphene Antonio H. Castro Neto. Trieste, August 2008. Outline. Coulomb impurity in graphene Vitor M. Pereira, Johan Nilsson, AHCN Phys.Rev.Lett. 99 , 166802 (2007); Vitor M. Pereira, Valeri Kotov, AHCN Phys. Rev. B 78 , 085101 (2008). - PowerPoint PPT Presentation
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Adatoms in Graphene
Antonio H. Castro Neto
Trieste, August 2008
Outline•Coulomb impurity in graphene Vitor M. Pereira, Johan Nilsson, AHCN Phys.Rev.Lett. 99, 166802 (2007); Vitor M. Pereira, Valeri Kotov, AHCN Phys. Rev. B 78, 085101 (2008).
•Anderson impurity in graphene Bruno Uchoa, Valeri Kotov, Nuno Peres, AHCN Phys. Rev. Lett. 101, 026805 (2008);
Bruno Uchoa, Chiung-Yuan Lin, Nuno Peres, AHCN
Phys.Rev.B 77, 035420 (2008).
-40 -20 0 4020Vg (V)
(1
/k
)
0
1
2
Nim (1012 cm-2)
(1
03 c
m2/V
s)
0
2
4
6
0 1 2
NO 2
Controlling scattering
Geim’s group
Tail Mobility (m2/V sec)
min
(e2 /
h) 12
8
4
01.41.21.00.80.60.40.20
16
10
8
6
4
2
0-50 0 50
Vg (V)
con
duct
ivit
y (m
S)
X 2
10
8
6
4
2
0-50 0 50
Vg (V)
con
duct
ivit
y (m
S) 10
8
6
4
2
0-50 0 50
Vg (V)
con
duct
ivit
y (m
S)
10
8
6
4
2
0-50 0 50
Vg (V)
con
duct
ivit
y (m
S)
4e2/h
4e2/h
Kim’s group
Artificial structures: Chemistry, engineering, material science
Hashimoto et al. Nature 430, 870 (04)
How do adatoms modify graphene’s properties ?
Pereira et al., Phys.Rev.Lett. 99, 166802 (2007);
3D Schroedinger l
Coupling
UndercriticalSupercritical
Andrei’s group
HIC Neutron stars
LmvF
C
ar
a
t
aL
C
21
50
06.0
107
E
N(E)
0
U0
Anderson’s Impurity Model
T>TK
00 00
Non-interacting: U=0
Broadening
EnergyEnergy
0
V=0
R
00
Mean-Field
00
The impurity moment can be switched on and off!
U = 1 eV
n_down
V=1eV, e0=0.2 eV
n_up
U = 40 meV
U = 0.1 eV
Conclusions
• Impurities in graphene behave in an unusual way when compared to normal metals and semiconductors.
• One can test theories of nuclear matter under extreme conditions.
• Control of the magnetic moment formation of transition metals using electric fields.
