Quantum conductance and indirect exchange interaction (RKKY interaction) Conductance of nano-systems with interactions coupled via conduction electrons: Effect of indirect exchange interactions cond-mat/0605756 to appear in Eur. Phys. J. B Yoichi Asada (Tokyo Institute of Technology) Axel Freyn (SPEC), JLP (SPEC). Interacting electron systems between Fermi leads: Effective one-body transmission and correlation clouds Rafael Molina, Dietmar Weinmann, JLP Eur. Phys. J. B 48, 243 (2005)
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Embed
Quantum conductance and indirect exchange interaction (RKKY interaction)
Quantum conductance and indirect exchange interaction (RKKY interaction). Conductance of nano-systems with interactions coupled via conduction electrons: Effect of indirect exchange interactions cond-mat/0605756 to appear in Eur. Phys. J. B Yoichi Asada (Tokyo Institute of Technology) - PowerPoint PPT Presentation
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Quantum conductance and indirect exchange interaction (RKKY interaction)
Conductance of nano-systems with interactions coupled via conduction electrons: Effect of indirect exchange interactions
cond-mat/0605756 to appear in Eur. Phys. J. B
Yoichi Asada (Tokyo Institute of Technology) Axel Freyn (SPEC), JLP (SPEC).
Interacting electron systems between Fermi leads:Effective one-body transmission and correlation clouds
Rafael Molina, Dietmar Weinmann, JLP Eur. Phys. J. B 48, 243 (2005)
Scattering approach to quantum transport
22
,2
UEth
e
V
IG Feff
UEt Feff ,
SContact (Fermi) Contact (Fermi)
S(U)Fermi Fermi
1. Nano-system inside which the electrons do not interact
One body scatterer
Many body scatterer
effective one body scatterer
Value of ?Size of the effective one body scatterer?
Relation with Kondo problem
Carbon nanotubeMolecule,Break junctionQuantum dot of high rs Quantum point contact g<1YBaCuO…
2. Nano-system inside which the electrons do interact
222
FEth
e
V
IG
How can we obtain the effective transmission coefficient?
The embedding method
How can we obtain ? Density Matrix Renormalization Group
Embedding + DMRG = exact numerical method.
Difficulty: Extension outside d=1
Permanent current of a ring embedding the nanosystem + limit of infinite ring size
2,UEtI Feff
I
How can we obtain the size of the effective one body scatterer?
2 scatterers in series
• Are there corrections to the combination law of one body scatterers in series? Yes
• This phenomenon is reminiscent of the RKKY interaction between magnetic moments.
Combination law for 2 one body scatterers in series
tt CF
T
SLST
Lcik
Lcik
L
S
Lk
tt
MMMM
e
eM
tt
rt
r
tM
F
F
42
42
*
*
*
22cos112
..
0
0
1
1
Half-filling: Even-odd oscillations + correction
The correction disappears when the length of the coupling lead increases with a power law
C
SC
L
LUALg
,
Correction:
Magnitude of the correction
U=2 (Luttinger liquid – Mott insulator)
RKKY interaction(S=spin of a magnetic ion or nuclear spin)