Physics

Dr. Bhaskaran Muralidharan
IIT Bombay

ABSTRACT: Semiconductor nanowire-superconductor hybrid systems provide a promising platform for hosting unpaired Majorana fermions and thus realizing fault-tolerant topological qubits. In this talk, starting from the basic tenets of quantum transport theory, we demonstrate how to adapt the Non-Equilibrium Green’s Function (NEGF) formalism to model quantum transport in normal (N)-superconductor (S) junctions. We analyze Josephson junctions based on semiconductor nanowires and derive the Andreev bound state spectrum and current-phase relations. Recently, [1], and [2] have reported oscillations in the critical supercurrent with an axial magnetic field. Our simulations indicate that this phenomenon arises from the interference of orbital angular momentum modes [3,4] of the cylindrical nanowire. We also add disorder and study its effect on the critical current oscillations, with an aim to gain a thoroughgoing understanding of the experiments.


[2] Zuo, et. al. Phys. Rev. Lett.119, 187704 (2017
[3] P. Sriram et. al., ArXiv:).
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