Leiden University Scholarly Publications

Persistent URL of this record https://hdl.handle.net/1887/3768509

In Collections

This item can be found in the following collections:

Chen, X. (2024)

Manipulation of superconductivity in van der Waals materials and thin films

Doctoral Thesis
Superconductivity refers to a phase of matter in which charge carriers can be moved without dissipating energy. In this special phase, unlike a perfect metal conductor, any external magnetic field lines are expelled from the material. The phenomenon has been a focus of attention both in fundamental science research as well as technological application ever since it was first discovered in Leiden in the year of 1911. Recent fast progress in nano-engineering, fabrication and characterisation enable two-dimensional devices to be realised relatively easily in the lab via top-down or/and bottom-up methods. Van der Waals materials and thin films can be fabricated now with good control and reproducibility. This has not only paved the way for studying clean superconductivity in two dimensions.
The advances in nanotechnology combined with the increasing understanding and exploration in solid state physics also allow more control over the superconducting properties of matter. This...Show moreSuperconductivity refers to a phase of matter in which charge carriers can be moved without dissipating energy. In this special phase, unlike a perfect metal conductor, any external magnetic field lines are expelled from the material. The phenomenon has been a focus of attention both in fundamental science research as well as technological application ever since it was first discovered in Leiden in the year of 1911. Recent fast progress in nano-engineering, fabrication and characterisation enable two-dimensional devices to be realised relatively easily in the lab via top-down or/and bottom-up methods. Van der Waals materials and thin films can be fabricated now with good control and reproducibility. This has not only paved the way for studying clean superconductivity in two dimensions.
The advances in nanotechnology combined with the increasing understanding and exploration in solid state physics also allow more control over the superconducting properties of matter. This thesis contributes to the study of conventional phonon-mediated superconductors by exploring the possibility of manipulating (quasi-) two-dimensional (2D) superconductors' properties through the careful design of the devices. The investigations reported in this thesis include clean 2D superconductivity via a top-down fabrication method of exfoliating van der Waals superconductor crystals; understanding critical current magnetic oscillation in van der Waals heterostructure Josephson Junctions; increasing critical current density of thin film superconductor through controlled oxidation. And ambitiously, the increasing of critical temperature of a superconductor by manipulating the material with a superperiodic potential.
Show less
Condensed matter physics
Superconductivity
2D materials
Josephson junctions
Thin film superconductors
Critical temperature enhancement
Engineering superconductors
All authors
Chen, X.
Supervisor
Molen, S.J. van der; Dood, M.J.A. de
Committee
Vermaekelbergh, D.A.M.; Ali, M.N.; Achúcarro, A.; Aarts, J.; Huber, M.I.; Oosterkamp, T.H.
Qualification
Doctor (dr.)
Awarding Institution
Leiden Institute of Physics (LION), Faculty of Science, Leiden University
Date
2024-07-02