We observe a series of discontinuities in the above gap current-voltage characteristics of highly transmissive NbySi superconductor-semiconductor interfaces. The bias at which each switch occurs decreases in quantized steps as a function of temperature and magnetic field. The observed step size is the same for both dependencies. We propose that the steps correspond to supercurrent quantization ...

Bulk rhombohedral Bi at ambient pressure is a well-known semimetal, and its transition to a superconductor has not been observed, at least down to 50 mK. We report that, unlike bulk rhombohedral Bi, granular Bi nanowires with well-defined rhombohedral grains of approximately 10 nm diameter, fabricated by electrochemically depositing Bi into porous polycarbonate membranes at ambient pressure, ar...

(Bi,Pb)–Sr−Ca–Cu–O glasses, annealed in proper conditions, transform into a granular metal and superconductor. As a result of annealing oxide superconductors belonging to the bismuth family (Bi,Pb)2Sr2CuOx, (Bi,Pb)2Sr2CaCu2Ox, and (Bi,Pb)2Sr2Ca2Cu3Ox crystallize. (Bi,Pb)–Sr– Ca–Cu–O glass-ceramic samples were obtained by annealing the amorphous solid at temperatures between 500◦C and 870◦C. The...

We demonstrate that a highly frustrated anisotropic Josephson junction array (JJA) on a square lattice exhibits a zero-temperature jamming transition, which shares much in common with those in granular systems. Anisotropy of the Josephson couplings along the horizontal and vertical directions plays roles similar to normal load or density in granular systems. We studied numerically static and dy...

The magnetoresistance of a granular superconductor in a strong magnetic field that destroys the gap in each grain is considered. It is assumed that the tunneling between grains is sufficiently large such that all conventional effects of localization can be neglected. A nontrivial sensitivity to the magnetic field comes from superconducting fluctuations leading to the formation of virtual Cooper...