Quasiparticle response of superconducting aluminum to electromagnetic radiation
Quasiparticle response of superconducting aluminum to electromagnetic radiation
The response of superconducting aluminum to electromagnetic radiation is investigated in broad frequency (45 MHz--40 GHz) and temperature ranges $(T>{T}_{c}/2)$ by measuring the complex conductivity. While the imaginary part probes the superfluid density (Cooper pairs), the real part monitors the opening of the superconducting energy gap and---most important here---the zero-frequency …