Related papers: Reflectionless tunneling in planar Nb/GaAs hybrid …
Coherent transport in Nb/GaAs superconductor-semiconductor microstructures is presented. The structures fabrication procedure is based on delta-doped layers grown by molecular-beam-epitaxy near the GaAs surface, followed by an As cap layer…
We investigate the phenomenon of reflectionless tunneling in ballistic normal-metal--superconductor (NS) structures, using a semiclassical formalism. It is shown that applied magnetic field and superconducting phase difference both impair…
Andreev-reflection dominated transport is demonstrated in Al/n-In0.38Ga0.62As superconductor-semiconductor junctions grown by molecular beam epitaxy on GaAs(001). High junction transparency was achieved in low-doped devices by exploiting Si…
Complete suppression of the native n-type Schottky barrier is demonstrated in Al/InGaAs(001) junctions grown by molecular-beam-epitaxy. This result was achieved by the insertion of Si bilayers at the metal-semiconductor interface allowing…
We report on the fabrication of highly transparent superconductor/normal metal/two-dimensional electron gas junctions formed by a superconducting NbN electrode, a thin (10nm) Au interlayer, and a two-dimensional electron gas in a InGaAs/InP…
We report the demonstration of hybrid high-Tc-superconductor-semiconductor tunnel junctions, enabling new interdisciplinary directions in condensed matter research. The devices were fabricated by our newly-developed mechanical bonding…
We study the magnetotransport in small hybrid junctions formed by high-mobility GaInAs/InP heterostructures coupled to superconducting (S) and normal metal (N) terminals. Highly transmissive superconducting contacts to a two-dimensional…
Planar tunneling junctions of the presumably unconventional superconductor FeSe were prepared and investigated. The junctions consisted of FeSe/AlOx/Ag multilayers patterned lithographically into mesa structures. Bias voltage dependent…
We study resonant tunneling through a superconducting double barrier structure in graphene as a function of the system parameters. At each barrier, due to the proximity effect, an incident electron can either reflect as an electron or a…
Phase-coherent diffusive transport through mesoscopic hybrid superconductor/normal metal tunneling structures is investigated. For a N-s-S two-barrier tunneling system with bulk S and N electrodes coupled by a mesoscopic superconducting…
We have formed superconducting contacts in which Cooper pairs incident from a thick In layer must move through a thin Nb layer to reach a semiconductor, either InAs or low temperature grown (LTG) GaAs. The effect of pair tunneling through…
The impact of junction transparency in driving phase-coherent charge transfer across diffusive semiconductor-superconductor junctions is demonstrated. We present conductivity data for a set of Nb-InAs junctions differing only in interface…
We study the sub-gap conductance of a ferromagnetic mesoscopic region attached to a ferromagnetic and a superconducting electrode by means of tunnel junctions. In the absence of the exchange field, the ratio $r= \gamma / \epsilon_T$ of the…
We correlate transmission electron microscope (TEM) pictures of superconducting In contacts to an AlGaAs/GaAs heterojunction with differential conductance spectroscopy performed on the same heterojunction. Metals deposited onto a (100)…
We investigate transport through hybrid structures consisting of two normal metal leads connected via tunnel barriers to one common superconducting electrode. We find clear evidence for the occurrence of non-local Andreev reflection and…
Experiments on hybrid superconducting normal-metal structures have revealed that even in the absence of tunnel junctions the onset of superconductivity can lead to a decrease in the electrical conductance by an amount many orders of…
Using the highly inhomogeneous fields of a magnetic substrate, tunable junctions between superconducting and normal state regions were created inside a thin film superconductor. The investigation of these junctions, created in the same…
Experimental and theoretical studies on transport in semiconductor samples with superconducting electrodes are reported. We focus on the samples close to metal-insulator transition. In metallic samples, a peak of negative magnetoresistance…
We demonstrate efficient spin-polarized tunneling between a ferromagnetic metal and a ferromagnetic semiconductor with highly mismatched conductivities. This is indicated by a large tunneling magnetoresistance (up to 30%) at low…
A magnetic field applied parallel to the two-dimensional hole system in the GaAs/AlGaAs heterostructure, which is metallic in the absence of an external magnetic field, can drive the system into insulating at a finite field through a well…