Solution of the tight-binding Bogoliubov-de Gennes equations for topological superconductivity

Postgraduate Thesis uoadl:2941843 12 Read counter

Unit:
Κατεύθυνση Φυσική των Υλικών
Library of the School of Science
Deposit date:
2021-04-05
Year:
2021
Author:
Rigas Spyridon
Supervisors info:
Καθηγητής Μαυρόπουλος Φοίβος, Τμήμα Φυσικής, ΕΚΠΑ
Professor Blügel Stefan, Department of Physics, RWTH Aachen
Καθηγητής Φραντζεσκάκης Δημήτριος, Τμήμα Φυσικής, ΕΚΠΑ
Original Title:
Solution of the tight-binding Bogoliubov-de Gennes equations for topological superconductivity
Languages:
English
Translated title:
Solution of the tight-binding Bogoliubov-de Gennes equations for topological superconductivity
Summary:
After reviewing the main aspects of the tight-binding Bogoliubov-de Gennes theory of superconductivity, we showed how the formalism of Green functions can be applied in order to study the effects of impurities within this framework. We then modelled superconducting surfaces and investigated how the gap’s properties are affected by the presence of single non-magnetic and magnetic impurities. After observing that magnetic impurities induce bound states inside the superconducting gap, we considered chains of magnetic atoms embedded in or adsorbed on the surface. Our findings indicated that for configurations where the magnetic chain forms a spin helix, a topologically non-trivial phase exists for the system, with localized Majorana zero modes emerging inside the spectral gap. Finally, we performed simulations with such chains in order to investigate how this topological phase is affected by parameters such as the chain’s length, or the spin helix’s rotation angle, and explored some of the conditions that must be met in order to realize this topological superconductor.
Main subject category:
Science
Keywords:
Condensed Matter, Correlated Electrons, Superconductivity, Topology, Topological Materials, Quantum Phase Transitions, Magnetism, YSR States, Majorana, Bogoliubov-de Gennes, BdG
Index:
No
Number of index pages:
0
Contains images:
Yes
Number of references:
66
Number of pages:
70
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