Magnetic field dependence of the critical superconducting current induced by the proximity effect in silicon

The magnetic field dependence of the critical superconducting current induced by the proximity effect in heavily boron-doped Si is studied experimentally. It is found that the critical current flowing through the $p$-type-Si-coupled junction decreases with increasing applied magnetic field. The critical current can be expressed as the product of three factors: the current induced by de Gennes's proximity effect, the exponential decrease due to pair breaking by the magnetic field, and the usual diffraction-pattern-like dependence on the magnetic field due to the Josephson effect. The second factor depends on the carrier concentration in the semiconductor. The local critical current shows a rapid decrease at the edge of the electrodes.