Directional electron filtering at a superconductor-semiconductor interface

Abstract

We evaluate the microscopically relevant parameters for electrical transport of hybrid superconductorsemiconductor interfaces. In contrast to the commonly used geometrically constricted metallic systems, we focus on materials with dissimilar electronic properties like low-carrier density semiconductors combined with superconductors, without imposing geometric confinement. We find an intrinsic mode-selectivity, a directional momentum-filter, due to the differences in electronic band structure, which creates a separation of electron reservoirs each at the opposite sides of the semiconductor, while at the same time selecting modes propagating almost perpendicular to the interface. The electronic separation coexists with a transport current dominated by Andreev reflection and low elastic backscattering, both dependent on the gate-controllable electronic properties of the semiconductor.

A review of thermal rectification in solid-state devices

“…Approaches to promote thermal rectification through asymmetric electron transport appear to be the most favourable, with the normal metal-superconductor junction-based device proposed by Martinez-Perez et al [31] a stark outlier in Fig. 16.…”

“…Martinez-Perez et al [31] subsequently fabricated a thermal diode involving a normal metal (Al 0.98 Mn 0.02 )-superconductor (Al) interface on a silicon wafer. Superconducting probes were tunnel-coupled to normal metal junctions separated by an insulating layer at either side of the central normal metal-insulator-superconductor segment, which could be operated as heaters or temperature sensors.…”

Confinement-induced zero-bias peaks in conventional superconductor hybrids

“…Another finite-size effect is related to the finite cross section of semiconducting junctions [95,96]. Indeed, the Majorana condition in these setups is only fulfilled by a few transverse modes [97].…”