Title: Kondo effect in Quantum dots / Carbon nanotubes
1Kondo effect in Quantum dots / Carbon nanotubes
- Journal Club 2008/05/20
- Fan Wu
2Kondo effect
L. Kouwenhoven, L. Glazman. Revival of the Kondo
effect. Physics World, 1, 33 (2001)
odd e in QD
magnetic impurities
normal metal
SC
even e in QD
even
odd
3s 0.22 for spin-half system
Nature 408, 342 (2000)
4- SWNT with gold leads
- Kondo ridge for odd-N at B0
- Bubbles for even-N at B0, yet ridges can be
formed at certain field BC, which related with
ground state (singlet S0) - lowest excited state
(triplet S1) energy gap Dt-s as
M. Pustilnik, et al., Quantumdots with even
number of electrons Kondo effect in a finite
magnetic field. Phys. Rev. Lett. 84, 1756 (2000).
5- 12nm gold bridge on Al/Al2O3
- Electromigration forms grain quantum dot,
with/without submonolayer of cobalt - Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction
introduce split zero-bias peak (SZBP)
6- Competition between the Kondo effect (energy
scale TK) and the RKKY coupling of the spin
(interaction strength I)
7Nature 434, 484 (2005)
8- Ti/Au electrodes with CVD grown SWNT
- dB orbital Kondo effect induced by anticrossing
band
- Unusually high TK 7.7K, ascribed to the
enhanced degeneracy (one electron SU(4) and
two-electron singlettriplet Kondo
B1.5T
9(No Transcript)
10- Cr/Au electrodes with CVD grown SWNT
Ng 1, 3
SU(2)
Ng 2
11- InAs quantum dots with Ti/Al electrodes
- Competition between Kondo and SC DltltkBT, Kondo
survive with SC leads DgtgtkBT, Coulomb blockade
12TK TK/(21/s-1)1/2, G(TK) G0/2, s0.22 for
spin-half system
13- Cr/Au electrodes with CVD grown SWNT
14Coulomb energy U 2.9 meV,orbital splitting
0.7 meV, single-particle level spacing DE 3.5
meV.
- Inelastic cotunneling with second-order
perturbation