(a) The quasiparticle density of states in a proximized Ta/Al bilayer with thicknesses 100/30 nm. The solid lines show the density of states in the two materials at their free interfaces and the dashed lines show the quasiparticle density of states on either side of the interface between the two materials. The energy gap is equal to 500 meV and the broadened peak in the tantalum layer is at . (b) The BCS counterpart density of states which only shows a singularity at the energy gap.
The two routes of down conversion in a thin film proximized superconductor. (a) Relaxation of a quasiparticle to the energy gap producing two extra quasiparticles. (b) Relaxation of a quasiparticle toward the energy gap via the energy gap of the higher energy gap material producing no extra quasiparticles. (c) A schematic representation of the quasiparticle density of states of a proximized superconducting bilayer averaged over the bilayer thickness.
The rate of phonon emission resulting from relaxations of a quasiparticle from energy to in the range of to (a) of a Ta/Al film 100/60 nm with an energy gap of and (b) of a BCS-type film with the same energy gap.
Ratio of quasiparticle yield in a proximized Ta/Al bilayer and in the BCS counterpart as a function of tantalum layer thickness for aluminum thicknesses 30, 60, and 100 nm.
Schematic representation of the DROID configuration.
Scatter plot of the total charge output, measuring a photon energy, against the ratio of the charges, measuring the position of absorption site, for the 100/30 nm Ta/Al DROID and a wavelength of 300 nm. The lines show a graphical representation of the selection of the different areas with the sections used to calculate the ratios indicated.
Ratio of the charge output of absorption in the STJ and in the absorber right next to the STJ for the three layouts at different bias voltages. The three lines are the calculated ratios.
Ratio of the charge output from the STJ and from the absorber just next to the STJ for the DROIDs with aluminum layer thickness of 30, 60, and 100 nm, all with a tantalum layer thickness of 100 nm. The dashed line is the predicted ratio for a BCS-type STJ with energy gap . The solid line is the ratio as calculated obtained with the model. The presented points are averages of the measured ratios at different photon energies in the range of 1.5–5 eV over which range the ratio is constant in all three cases. The ratios for the bilayers with 30 nm aluminum have been measured at a bias voltage of and the ratios for the bilayers with 60 and 100 nm aluminum have been measured at .
Article metrics loading...
Full text loading...