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Digital archive of theses discussed at the University of Pisa

 

Thesis etd-06082021-112150


Thesis type
Tesi di dottorato di ricerca
Author
PUGLIA, CLAUDIO
URN
etd-06082021-112150
Thesis title
Gate control of superconductivity in elemental BCS systems
Academic discipline
FIS/03
Course of study
FISICA
Supervisors
tutor Dott. Giazotto, Francesco
relatore Dott. De Simoni, Giorgio
Keywords
  • field-effect
  • Gate-control
  • nanotransistor
  • Superconductivity
Graduation session start date
14/06/2021
Availability
Withheld
Release date
14/06/2061
Summary
It was recently demonstrated the possibility to tune, through the application of a control gate voltage, the superconducting properties of mesoscopic devices based on Bardeen-Cooper-Schrieffer metals. In spite of the several experimental evidence obtained on different materials and geometries, a description of the microscopic mechanism at the basis of such unconventional effect has not been provided yet. This thesis discusses the technological potential of gate control of superconductivity in metallic superconductors and revises the experimental results which provide information regarding a possible thermal origin of the effect: I review experiments performed on high critical temperature elemental superconductors (niobium and vanadium) and show how devices based on these materials can be exploited to realize basic electronic tools such as, e. g., a half-wave rectifier. Moreover, I discuss the origin of the gating effect by showing the gate-driven suppression of the supercurrent in a suspended titanium wire and by providing a comparison between thermal and electric switching current probability distributions. Furthermore, we discuss the cold field-emission of electrons from the gate by means of finite element simulations and compare the results with experimental data. Finally, the presented data provide a strong indication regarding the unlikelihood of thermal origin of the gating effect.
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