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Archivio digitale delle tesi discusse presso l’Università di Pisa

Tesi etd-06082021-112150


Tipo di tesi
Tesi di dottorato di ricerca
Autore
PUGLIA, CLAUDIO
URN
etd-06082021-112150
Titolo
Gate control of superconductivity in elemental BCS systems
Settore scientifico disciplinare
FIS/03
Corso di studi
FISICA
Relatori
tutor Dott. Giazotto, Francesco
relatore Dott. De Simoni, Giorgio
Parole chiave
  • field-effect
  • nanotransistor
  • Gate-control
  • Superconductivity
Data inizio appello
14/06/2021
Consultabilità
Non consultabile
Data di rilascio
14/06/2061
Riassunto
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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