Description du sujet de thèse

The main objectives of this PhD project are to develop the molecular beam epitaxy (MBE) of superconductors (Al, Pb, Sn) at cryogenic temperature (100 K) on insulating (Al2O3), semiconductor (GaAs, InAs) and Topological Insulators (BiSb) substrates, to characterize their structural properties and to probe the superconductivity at low temperature with electrical measurements. Such hybrid interfaces are the fundamental building blocks for Qubits based on Josephson Junctions (IBM, Intel, AWS) or Majorana Zero Modes (Microsoft). In the current systems, Aluminum is the most used superconductor due to the deposition techniques (sputtering, evaporation, MBE) and the quality of the synthetized layer. Unfortunately, the Al layer is polycrystalline in most of the cases (sputtering, evaporation), and presents defects in standard MBE processes.

The first objective of the PhD student will be to develop the Cryo-MBE growth of Al, Pb Sn layers on insulating and semiconducting substrates (Al2O3, GaAs) and to demonstrate the mono-crystallinity of such layers. The second objective is to fabricate characterization devices (Hall bars and superconducting wires) using electron beam lithography in the LAAS cleanroom. The third objective is to characterize the superconducting behavior of such devices using magnetotransport set-ups.

Contexte de travail

The PhD student will work at LAAS, he/she will be hosted by the Materials and Processes for Nanoelectronics (MPN) group. The MPN team has been created in 2012 and focus on the synthesis of new materials, their advanced structural characterization, the development of technological processes for building new devices and finally their electrical characterizations.

Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.

Contraintes et risques

Work in the cleanroom