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Quasi-static transport measurements are employed to characterize a few electron quantum dot electrostatically defined in a GaAs/AlGaAs heterostructure. The gate geometry allows observations on one and the same electron droplet within a wide…
The precise control of a bilayer system consisting of two adjacent two-dimensional electron gases (2DEG) is demonstrated by using a novel planar back-gate approach based on ion implantation. This technique overcomes some common problems of…
Hybrid InSb nanowire-superconductor devices are promising for investigating Majorana modes and topological quantum computation in solid-state devices. An experimental realisation of ballistic, phase-coherent superconductor-nanowire hybrid…
We have studied ballistic transport in a 1D channel formed using surface gate techniques on a back-gated, high-mobility, bilayer 2D hole system. At millikelvin temperatures, robust conductance quantization is observed in the quantum wire…
We investigated the gate control of a two-dimensional electron gas (2DEG) confined to InSb quantum wells with an Al2O3 gate dielectric formed by atomic layer deposition on a surface layer of Al0.1In0.9Sb or InSb. The wider bandgap of…
Highly transmissive ballistic junctions are demonstrated between Nb and the two-dimensional electron gas formed at an InAs/AlSb heterojunction. A reproducible fabrication protocol is presented yielding high critical supercurrent values.…
We report magneto-transport measurements of quasi-1-dimensional (1D) Al-InAs nanowires produced via etching of a hybrid superconductor-semiconductor two-dimensional electron gas (2DEG). Tunnel spectroscopy measurements above the…
Single atom junctions between superconducting niobium leads are produced using the Mechanically Controllable Break Junction technique. The current-voltage characteristics of these junctions are analysed using an exact formulation for a…
We present an extensive experimental and theoretical study of the proximity effect in InAs nanowires connected to superconducting electrodes. We fabricate and investigate devices with suspended gate-controlled nanowires and nonsuspended…
We propose and investigate a spin transistor device consisting of two ferromagnetic leads connected by a two-dimensional topological insulator as the channel material. It exploits the unique features of the topological spin-helical edge…
We investigate the low-energy quantum transport in the ballistic normal metal-insulator -superconductor junction in the presence of magnetic field creating Abrikosov vortices in the superconductor. Within the Bogolubov- de Gennes theory we…
We present a theoretical analysis of the current-voltage characteristics of a ballistic superconductor-normal-superconductor (SNS) junction, in which a strip of graphene is coupled to two superconducting electrodes. We focus in the…
We investigate the current-voltage characteristics of high-transparency superconductor-insulator-normal metal (SIN) junctions with the specific tunnel resistance below 30 kOhm per square micron. The junctions were fabricated from different…
Transport in InAs/GaSb heterostructures with different InAs layer thicknesses is studied using a six-terminal Hall bar geometry with a 2-$\mu$m edge channel length. For a sample with a 12-nm-thick InAs layer, non-local resistance…
Electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the…
In the last six years, Indium selenide (InSe) has appeared as a new van der Waals heterostructure platform which has been extensively studied due to its unique electronic and optical properties. Such as transition metal dichalcogenides…
Two-dimensional (2D) transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) have been intensively investigated because of their exclusive physical properties for advanced electronics and optoelectronics. In the present…
We investigate electron transport through the interface between a niobium superconductor and the edge of a two-dimensional semimetal, realized in a 20~nm wide HgTe quantum well. Experimentally, we observe that typical behavior of a single…
We report a giant inverse proximity effect that arises in the low-dimensional devices and is crucially different from proximity in the standard superconductor-normal-superconductor (S/N/S) junctions. The normal conductors induce a giant…
We study a superconducting quantum point contact made of a narrow In$_{0.75}% $Ga$_{0.25}$As channel with Nb proximity electrodes. The narrow channel is formed in a gate-fitted constriction of InGaAs/InAlAs/InP heterostructure hosting a…