Abstract
We report nonequilibrium transport measurements of gate-tunable Andreev bound states in a carbon nanotube quantum dot coupled to two superconducting leads. In particular, we observe clear features of two types of Kondo ridges, which can be understood in terms of the interplay between the Kondo effect and superconductivity. In the first type (type I), the coupling is strong and the Kondo effect is dominant. Levels of the Andreev bound states display anticrossing in the middle of the ridge. On the other hand, crossing of the two Andreev bound states is shown in the second type (type II) together with the 0-π transition of the Josephson junction. Our scenario is well understood in terms of only a single dimensionless parameter, kBTKminâ¡ /Δ, where TKminâ¡ and Δ are the minimum Kondo temperature of a ridge and the superconducting order parameter, respectively. Our observation is consistent with measurements of the critical current, and is supported by numerical renormalization group calculations.
| Original language | English |
|---|---|
| Article number | 076803 |
| Journal | Physical Review Letters |
| Volume | 110 |
| Issue number | 7 |
| DOIs | |
| Publication status | Published - 2013 Feb 13 |
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Transport measurement of andreev bound states in a kondo-correlated quantum dot. / Kim, Bum Kyu; Ahn, Ye Hwan; Kim, Ju Jin; Choi, Mahn-Soo; Bae, Myung Ho; Kang, Kicheon; Lim, Jong Soo; López, Rosa; Kim, Nam.
In: Physical Review Letters, Vol. 110, No. 7, 076803, 13.02.2013.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Transport measurement of andreev bound states in a kondo-correlated quantum dot
AU - Kim, Bum Kyu
AU - Ahn, Ye Hwan
AU - Kim, Ju Jin
AU - Choi, Mahn-Soo
AU - Bae, Myung Ho
AU - Kang, Kicheon
AU - Lim, Jong Soo
AU - López, Rosa
AU - Kim, Nam
PY - 2013/2/13
Y1 - 2013/2/13
N2 - We report nonequilibrium transport measurements of gate-tunable Andreev bound states in a carbon nanotube quantum dot coupled to two superconducting leads. In particular, we observe clear features of two types of Kondo ridges, which can be understood in terms of the interplay between the Kondo effect and superconductivity. In the first type (type I), the coupling is strong and the Kondo effect is dominant. Levels of the Andreev bound states display anticrossing in the middle of the ridge. On the other hand, crossing of the two Andreev bound states is shown in the second type (type II) together with the 0-π transition of the Josephson junction. Our scenario is well understood in terms of only a single dimensionless parameter, kBTKminâ¡ /Δ, where TKminâ¡ and Δ are the minimum Kondo temperature of a ridge and the superconducting order parameter, respectively. Our observation is consistent with measurements of the critical current, and is supported by numerical renormalization group calculations.
AB - We report nonequilibrium transport measurements of gate-tunable Andreev bound states in a carbon nanotube quantum dot coupled to two superconducting leads. In particular, we observe clear features of two types of Kondo ridges, which can be understood in terms of the interplay between the Kondo effect and superconductivity. In the first type (type I), the coupling is strong and the Kondo effect is dominant. Levels of the Andreev bound states display anticrossing in the middle of the ridge. On the other hand, crossing of the two Andreev bound states is shown in the second type (type II) together with the 0-π transition of the Josephson junction. Our scenario is well understood in terms of only a single dimensionless parameter, kBTKminâ¡ /Δ, where TKminâ¡ and Δ are the minimum Kondo temperature of a ridge and the superconducting order parameter, respectively. Our observation is consistent with measurements of the critical current, and is supported by numerical renormalization group calculations.
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U2 - 10.1103/PhysRevLett.110.076803
DO - 10.1103/PhysRevLett.110.076803
M3 - Article
AN - SCOPUS:84874065276
VL - 110
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 7
M1 - 076803
ER -