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David Wander- ​ESR 2,  September 2018 - August 2020 and December 2020- November 2021

Institut Néel, CNRS and Université Grenoble Alpes, Grenoble, France

Master thesis: "STM investigation of graphene on SiC"

Growing graphene on SiC allows for large-scale production of high quality graphene structures. For example, in nanoribbons grown by this technique, ballistic transport at room temperature was reported. Therefore, this is a very promising approach for future graphene based electronics.

In my master thesis I used a low temperature STM to characterize graphene grown on SiC using a novel approach. Apart from the sample’s topography, I studied its electronic properties by scanning tunneling spectroscopy and the analysis of quasi particle interference patterns.

Personal Training Committee

Main Supervisor: Clemens Winkelmann, CNRS

Co-supervisor: Elke Scheer, UKON

Mentor: Khaled Karrai, ATTO

Planned secondments

At Chalmers (March 2019) to get trained on molecular and graphene-based electronics,

At ATTO (June/July 2019) to learn about AFM under extreme conditions,

At UKON, (December 2020) to get trained on simulation of tunnel spectra in hybrid superconductor-ferromagnet systems

PhD project

Adjustable magnetism of a quantum dot coupled to a superconductor

Objectives: What is the electronic spectrum and spatial extent of Andreev bound states in a QD coupled to a superconductor? According to the parity of the QD electronic occupation, it can behave as a magnetic impurity or not, producing a scattering centre for the spatial diffusion of Cooper pairs. I will answer this important and quite generic question using a novel approach. In collaboration for the theory with Early Stage Researchers 3 and 7, this study will bring a deeper knowledge of the nature of Andreev localised states that are key for the understanding of mesoscopic superconducting structures. I will fabricate superconducting substrates (niobium, or rhenium, inert when epitaxial) covered with a network of gate electrodes that are isolated from the substrate. I will make use of an all-metal mask lift-off recipe already available at CNRS, enabling the use of refractory metals like Nb without contamination. Nanoparticles (or molecules) will be deposited on the superconducting substrate. The coupling to the gate will be strong for the nanoparticles deposited close to the gates. The gate electrodes will be used to adjust the occupancy of the electronic nanoparticle, which will tune the local magnetism. By performing scanning tunneling spectroscopy in the vicinity of particles with a variable coupling to the superconducting plane, I will study the competition of superconductivity and the Kondo effect in real space, with unprecedented energy resolution. I will also collaborate with Early Stage Researcher 10 on the spectroscopy of graphene nanoribbons.

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