Tuning the Josephson current in carbon nanotubes with the Kondo effect

被引：105

作者：

Eichler, A. ^{[1
]}

Deblock, R. ^{[2
]}

Weiss, M. ^{[1
]}

Karrasch, C. ^{[3
,4
]}

Meden, V. ^{[3
,4
]}

Schoenenberger, C. ^{[1
]}

Bouchiat, H. ^{[2
]}

机构：

[1] Univ Basel, Dept Phys, CH-4056 Basel, Switzerland

[2] Univ Paris 11, CNRS, UMR 8502, Phys Solides Lab, F-91405 Orsay, France

[3] Rhein Westfal TH Aachen, Inst Theoret Phys A, D-52056 Aachen, Germany

[4] Rhein Westfal TH Aachen, JARA Fundamentals Future Informat Technol, D-52056 Aachen, Germany

来源：

PHYSICAL REVIEW B | 2009年 / 79卷 / 16期

关键词：

carbon nanotubes; Josephson effect; Kondo effect; superconducting energy gap; MAGNETIC-ALLOYS; QUANTUM DOTS; IMPURITIES; INTERFERENCE; SUPERCURRENT; JUNCTIONS; BARRIER;

D O I：

10.1103/PhysRevB.79.161407

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We investigate the Josephson current in a single wall carbon nanotube connected to superconducting electrodes. We focus on the parameter regime in which transport is dominated by Kondo physics. A sizeable supercurrent is observed for odd number of electrons on the nanotube when the Kondo temperature T-K is sufficiently large compared to the superconducting gap. On the other hand when, in the center of the Kondo ridge, T-K is slightly smaller than the superconducting gap, the supercurrent is found to be extremely sensitive to the gate voltage V-BG. Whereas it is largely suppressed at the center of the ridge, it shows a sharp increase at a finite value of V-BG. This increase can be attributed to a doublet-singlet transition of the spin state of the nanotube island leading to a pi shift in the current phase relation. This transition is very sensitive to the asymmetry of the contacts and is in good agreement with theoretical predictions.

引用

页数：4

共 35 条

[1] VOLTAGE DUE TO THERMAL NOISE IN DC JOSEPHSON EFFECT [J].