Enhanced vortex damping by eddy currents in superconductor-semiconduc tor hybrids

An enhancement of vortex-motion damping in thin Pb/In superconducting films is obtained through coupling to an adjacent two-dimensional electron gas formed in a modulation-doped GaAs/AlGaAs heterostructure. This effect is observed by monitoring the power dissipation at the superconductor in the vortex state while 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 generation of eddy currents in the electron gas by moving flux lines. In the regime of filamentary and channel vortex flow, eddy-current damping leads to striking dissipation breakdown due to stopping of entire vortex channels.