Scanning gate microscopy measurements on a superconducting single-electron transistor
- 29 April 2009
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 79 (13), 134530
- https://doi.org/10.1103/physrevb.79.134530
Abstract
We present measurements on a superconducting single-electron transistor (SET) in which the metallic tip of a low-temperature scanning force microscope is used as a movable gate. We characterize the SET through charge stability diagram measurements and compare them to scanning gate measurements taken in the normal conducting and the superconducting states. The tip-induced potential is found to have a rather complex shape. It consists of a gate voltage-dependent part and a part which is independent of gate voltage. Further scanning gate measurements reveal a dependence of the charging energy and the superconducting gap on the tip position and the voltage applied to it. We observe an unexpected correlation between the magnitude of the superconducting gap and the charging energy. The change in can be understood to be due to screening, however the origin of the observed variation in remains to be understood. Simulations of the electrostatic problem are in reasonable agreement with the measured capacitances.
Keywords
This publication has 27 references indexed in Scilit:
- Measurement of the tip-induced potential in scanning gate experimentsPhysical Review B, 2007
- Discrete charging of traps visualized by scanning gate experiments on a quantum point contactPhysical Review B, 2007
- Classical Hall effect in scanning gate experimentsPhysical Review B, 2006
- Conductance Quantization at a Half-Integer Plateau in a Symmetric GaAs Quantum WireScience, 2006
- Imaging Transport Resonances in the Quantum Hall EffectPhysical Review Letters, 2005
- Spatially highly resolved study of AFM scanning tip–quantum dot local interactionNew Journal of Physics, 2005
- Spatially Resolved Manipulation of Single Electrons in Quantum Dots Using a Scanned ProbePhysical Review Letters, 2004
- Non-Gaussian distribution of nearest-neighbour Coulomb peak spacings in metallic single-electron transistorsEurophysics Letters, 2000
- Observation of combined Josephson and charging effects in small tunnel junction circuitsPhysical Review Letters, 1989
- Superconducting Transition in AluminumPhysical Review B, 1958