Transmission formalism for supercurrent flow in multiprobe superconductor-semiconductor-superconductor devices

A theoretical study is given of supercurrent flow in a one-dimensional semiconductor channel coupled to superconductors at both ends. In addition, the channel is coupled to a semiconductor reservoir by means of a junction with variable coupling strength ε. The supercurrent I(φ) is calculated from the phase-coherent propagation of electronlike and holelike excitations emitted by the superconductor reservoirs, together with electron and hole excitations from the semiconductor reservoir. The effect of temperature and ε on I(φ) is studied. It is shown that a voltage applied between the semiconductor reservoir and the superconductors modifies the I(φ) relation, even in the limit ε→0.

Charge exchange processes in low-energy He+ ion scattering from Si and Pd2Si surfaces

The surface of Si and thin layers of Pd2Si on Si have been studied by low-energy He+ ion scattering. The occurrence of the observed low-energy tails is attributed to reionization at the surface of He neutrals scattered from subsurface layers. It is shown that the tails provide valuable in-depth information