1. |
- Bauch, Thilo, 1972, et al.
(författare)
-
Correlated quantization of supercurrent and conductance in a superconducting quantum point contact
- 2005
-
Ingår i: Physical Review B. ; 71:17, s. 174502-
-
Tidskriftsartikel (refereegranskat)abstract
- We have measured the supercurrent and conductance of a superconducting quantum point contact in a superconductor two-dimensional electron gas-superconductor Josephson junction. We observe that the supercurrent and conductance change stepwise in a correlated manner as a function of the gate voltage. This was achieved by simultaneous measurement of the supercurrent and conductance at high bias from the same current voltage characteristic.
|
|
2. |
|
|
3. |
|
|
4. |
|
|
5. |
|
|
6. |
- Greibe, Tine, 1974, et al.
(författare)
-
Are "Pinholes" the Cause of Excess Current in Superconducting Tunnel Junctions? A Study of Andreev Current in Highly Resistive Junctions
- 2011
-
Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 106:9
-
Tidskriftsartikel (refereegranskat)abstract
- In highly resistive superconducting tunnel junctions, excess subgap current is usually observed and is often attributed to microscopic pinholes in the tunnel barrier. We have studied the subgap current in superconductor-insulator-superconductor (SIS) and superconductor-insulator-normal-metal ( SIN) junctions. In Al/AlOx/Al junctions, we observed a decrease of 2 orders of magnitude in the current upon the transition from the SIS to the SIN regime, where it then matched theory. In Al/AlOx/Cu junctions, we also observed generic features of coherent diffusive Andreev transport in a junction with a homogenous barrier. We use the quasiclassical Keldysh-Green function theory to quantify single- and two-particle tunneling and find good agreement with experiment over 2 orders of magnitude in transparency. We argue that our observations rule out pinholes as the origin of the excess current.
|
|
7. |
- Greibe, Tine, 1974, et al.
(författare)
-
Improvement of chip design to reduce resonances in subgap regime of Josephson junctions
- 2009
-
Ingår i: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6588 .- 1742-6596. ; 150, s. 052063-
-
Konferensbidrag (refereegranskat)abstract
- Excess current peaks in the IV curves of SIS Josephson junctions have been observed by some groups [1–3]. These peaks have the shape of a resonance as a function of voltage. The resonances appear in the subgap regime of the junctions and the subgap current (leakage current) is concealed. The positions of the resonances do not change as a magnetic field is applied to the junctions, but their amplitude decreases when the supercurrent is suppressed. We have measured the subgap current of Al/AlOx/Al junctions and we show that these resonances are due to resonant modes in the chip design which are excited by the ac-Josephson effect. We present a chip design that decreases the amplitude of the resonances to a such degree that the subgap current is quantifiable.
|
|
8. |
|
|
9. |
|
|
10. |
|
|