Experiments on Vortex Damping in Novel Superconductor-2D-Electron-Gas Hybrid Structures

Abstract

We have measured the power dissipation in thin Pb/In superconducting films which are coupled to an adjacent two‐dimensional electron gas formed in a modulation‐doped GaAs/AlGaAs heterostructure. An enhancement of vortex‐motion damping at the superconductor is obtained by increasing the density of the electron gas using a gate voltage. Quantitative agreement is found with calculations based on a viscous model of vortex damping which considers the generation of eddy currents in the electron gas by moving flux lines. Eddy‐current damping is much more pronounced in the regime of filamentary and channel vortex flow, as compared to the free‐flux flow case, leading to striking reductions in dissipation due to stopping of entire vortex channels.