Masters Defense: Magnus Rønne Lykkegård

Spectroscopy of Andreev Bound States - in One Dimonsional Hybrid Superconductor-Semiconductor Nanowires

In this thesis, we measure a hybrid device, which is proposed to be able to achieve an effective 1D p-wave superconductor, hosting Majorana zero modes. We focus on the challenges of coupling two superconducting wires through a quantum dot. We show that we can couple a mesoscopic quantum dot to the Andreev bound states that two superconducting wires host, at low parallel magnetic fields.  We demonstrate that we are fully able to control the trivial Andreev bound states using a magnetic field parallel to the superconducting nanowires and electrostatic gates. We show that the energy levels of the quantum dot can hybridize with the Andreev bound state energy levels, and also observe phase dependence in this regime indicating coherent transport of the electrons/quasiparticles through the two superconductors. 

Lastly, we introduce the concept of quantum chaos in an Andreev billiard geometry. We show preliminary experimental result where we can resolve the statistics of the level spacings in a chaotic billiard with particle-hole symmetry.


Meeting ID: 672 6034 7061
Passcode: 154650