Towards probing zero energy bound states with circuit QED in topological insulator junctions
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Nanotechnology (MPNAT), MSc
Publicerad
2023
Författare
Alcalde Herraiz, Núria
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Majorana fermions are aimed to be observed in a spin-non-degenerate system where
particle-hole symmetry is imposed. Such a landscape was proposed by Fu and Kane
to be formed at the interface between a topological insulator and a superconductor.
Topological insulators are insulating materials in the bulk, but that present metallic
states with spin non-degeneracy at the surface. These metallic states in the vicinity
of an ordinary superconductor become superconducting by proximity effect imposing
the particle-hole symmetry, hence an scenario were Majorana fermions observation
is possible.
Taking first steps towards Majorana engineering, the aim of the thesis is to study the
energy band structure of a STIS junction. The STIS junction studied was made from
bismuth selenide nanowires and aluminium electrode contacts and then embedded in
a RF-SQUID loop coupled to a resonator. This configuration allowed to characterize
the band structure of the STIS junction probing its susceptibility through microwave
reflectometry measurements. The experimental data was then compared to an STIS
short ballistic junction model obtaining a relaxation parameter γD = 2 GHz and
a microwave transitions rate of γND = 3 GHz for probing frequency 4.20 GHz and
γND = 10 GHz at 8.16 GHz.
Beskrivning
Ämne/nyckelord
majorana fermions, topological insulator, josephson junction, band structure, susceptibility, microwave reflectometry