This thesis studies thermoelectric transport in a magnetic topological insulator strip covered by two superconducting islands. The two islands split the strip into a five-region NSNSN junction. The insulator sits in the quantum anomalous Hall phase, and the proximity-induced pairing places each island in the chiral topological superconductor phase that hosts a single Majorana edge mode. We compute the linear-response transport with the scattering-matrix (Landauer-Büttiker) formalism.
The main quantities are the dimensionless Onsager integrands for charge and for heat, together with the conductances G(T) and K(T), as functions of the superconducting phase difference and the junction lengths. The charge and heat integrands oscillate out of phase with ∆φ. This opposite response keeps the heat conductance near zero and the charge conductance large. The junction conducts charge well and heat poorly, the reverse of an ordinary metal. The Wiedemann-Franz law breaks down across every geometry studied. The NSNSN junction works as a phase-tunable thermoelectric probe of its topological state.
Jury: Sungguen Ryu, Javier Osca, Rosa López
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