CUED Publications database

Magneto-conductance oscillation in hybrid superconductor-semiconductor- superconductor planar Josephson junctions

Delfanazari, K and Puddy, R and Ma, P and Yi, T and Cao, M and Gul, Y and Ritchie, D and Joyce, H and Kelly, M and Smith, C (2016) Magneto-conductance oscillation in hybrid superconductor-semiconductor- superconductor planar Josephson junctions. In: Frontiers in Condensed Matter Physics, Bristol, UK, 2017-1-9 to 2017-1-10.

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Distinct new properties of superconductors combined semiconductors could be achieved in hybrid superconductor-semiconductor (S-Sm) structures using the proximity effect. Here we present our experimental results on proximity induced superconductivity in a high-mobility two dimensional electron gas (2DEG) in Indium gallium arsenide (InGaAs) heterostructures. Niobium (Nb) material was used as superconducting contacts. The fabrication process and interface transparency of several planar Nb-2DEG-Nb Josephson junctions on a chip, measurements of deferential conductance, and critical current variation with temperature and magnetic field will be discussed. The magneto-conductance measurements and the quantum transport of junctions were measured at a base temperature of 40 mK. Owing to Andreev reflections at the S-Sm interfaces, the differential resistance (dV/dI) versus V curve shows the well-known subharmonic energy gap structure (SGS) at V=2Δ/ne where the Δ is Nb superconducting gap. The differential conductance (dI/dV) versus magnetic field B has its maximum at zero field and decreases by increasing the magnetic field up to 3 T. Above this point it reaches a constant value indicating that the junction completely turns to the normal state. When decreasing the magnetic field to below +0.4 T there is hysteresis in positive fields accompanied by oscillations of magneto-conductance with a periodicity of ~15 mT between +0.05 and 0 T. The same effect could also be seen for negative fields. Both the hysteresis and periodic oscillation effects are strongly temperature dependent. The possible reasons for these effects will be discussed during the talk.

Item Type: Conference or Workshop Item (UNSPECIFIED)
Divisions: Div B > Solid State Electronics and Nanoscale Science
Depositing User: Cron Job
Date Deposited: 17 Jul 2017 19:09
Last Modified: 18 Aug 2020 12:28