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David Wander presents

 Investigation of mesoscopic superconductivity by low temperature scanning tunneling microscopy

Monday, September 12th 2022 at 14:00

Seminar room – Building A –  CNRS

Link visio: https://univ-grenoble-alpes-fr.zoom.us/j/94643755488?pwd=dExWVjJ2emlIaU13K3FkV0JlWG1XZz09

Meeting ID: 946 4375 5488 | Passcode: 001999

The defence will be in English.



Since its development in the 1980s, the scanning tunneling microscope (STM) has become a workhorse in solid state physics. It offers a combination of atomically resolved topographical as well as spectroscopic information inaccessible by other means. In recent years, ultra-lowtemperature STMs working at millikelvin temperatures have been developed to resolve smaller and smaller energy scales. In my thesis, I built such a setup operating at an effective temperature of 140mK in a 50mK refrigerator. Additionally, the setup is equipped with an ultra highvacuum preparation chamber operating at 2e-10 mbar for controlling the sample surface on an atomic level.

After benchmarking this system, I show its first application on epitaxial monolayer NbSe2, a material hosting exotic Ising superconductivity and being a great platform for investigating superconductivity in the two-dimensional limit. In combination with magnetic superstructures, topological superconductivity in form of Majorana zero modes is expected to arise. Being topologically protected from decoherence, these states are promising candidates for topological quantum computing.