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Archivio digitale delle tesi discusse presso l’Università di Pisa

Tesi etd-08102023-205134


Tipo di tesi
Tesi di laurea magistrale
Autore
CIONI, FRANCESCO
URN
etd-08102023-205134
Titolo
Thermoelectricity in Coherent Systems with Broken Time-Reversal Symmetry
Dipartimento
FISICA
Corso di studi
FISICA
Relatori
relatore Dott. Taddei, Fabio
correlatore Prof. Polini, Marco
Parole chiave
  • noise
  • quantum
  • scattering
  • superconductors
  • thermoelectricity
Data inizio appello
13/09/2023
Consultabilità
Completa
Riassunto
Conversion of heat to work has been an intense subject of study from both a technological and a fundamental standpoint. Due to the understanding of microscopic quantum phenomena and to the ability to fabricate nanoscopic devices where these phenomena are relevant, we have become increasingly interested in characterising the thermoelectric response of very small systems. In these systems the moving parts are electrons, phonons, etc. in the form of steady-state currents.
In this thesis we are mainly interested in studying the thermoelectric properties of a specific hybrid system which breaks time-reversal symmetry, the Andreev interferometer, both in the linear and non-linear regime. An Andreev interferometer is a system made of normal terminal attached to two superconducting terminals. In this thesis, to add a more pronounced energy dependence, we include a quantum dot between the normal terminal and each superconductor. Due to the interplay between superconductivity and the absence of TRS, this system shows quite different behaviours with respect to normal systems. In particular, a peculiarity is the presence of strong interference effects introduced by the phase difference ∆φ set between the order parameters of the two superconductors. This reflects in peculiar transport properties and thermoelectric effects which can be turned on and off by simply adjusting these phases. Another interesting aspect that we investigate deeply is the noise in charge and heat current.
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