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Seminário do DFMT com o Prof. Eduardo Lee (IFIMAC)

Data do Evento: 
10/04/2017 - 16:00 até 18:00

SEMINÁRIO DO DEPARTAMENTO DE FÍSICA DOS MATERIAIS E MECÂNICA - FMT

“Sub-Gap Excitations in a Hybrid Superconductor-semiconductor Nanowire Quantum Dot”

Prof. Dr. Eduardo J. H. Lee, Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid

Dia: 10 de abril, segunda-feira, às 16h.

Local: Sala de Seminários José Roberto Leite, Edifício Alessandro Volta (bloco C).

Abstract:

The combination of superconductors and low-dimensional semiconductors embodies a rich, yet largely unexplored physics. In this talk, I will address the prototypical case of a quantum dot coupled to a superconducting contact - an artificial, tunable analogue of a magnetic impurity in a superconductor. This hybrid system is characterized by sub-gap excitations known as Andreev or Yu-Shiba-Rusinov bound states, which result from an interesting competition between the superconducting proximity effect, Coulomb blockade and Kondo correlations. We employ nanowirebased quantum dots coupled strongly to a superconductor and weakly to a normal metal probe, to study the above Andreev states by tunneling spectroscopy. First, we exploit the ability to tune the tunnel coupling between the quantum dot and the superconductor to study the energy scaling of Andreev levels. Finally, we study the impact of an external magnetic field on these low energy-excitations and report, for the first time, spin-polarized Andreev states. Importantly, these spin-polarized Andreev levels are known to be precursors of a topological superconductor. This work thus paves the way for the pursuit of proposals directed at engineering topological superconductors (and Majorana zero modes) from quantum dot arrays.

Data de Término: 
10/04/2017 - 16:00

Desenvolvido por IFUSP