Robust Signatures of Majorana Fermions in a Semiconductor Quantum Ring

TL;DR

This study suggests that semiconductor quantum rings with strong spin-orbit coupling and proximity-induced superconductivity can host Majorana fermions, evidenced by near-degenerate ground states and well-separated wave functions, indicating potential for experimental observation.

Contribution

The paper demonstrates the theoretical possibility of Majorana fermions in small semiconductor quantum rings, highlighting specific conditions and signatures for their detection.

Findings

Majorana fermions are indicated by near-degenerate ground states.

Majorana wave functions are well separated in angular coordinates.

Conditions for Majorana presence depend on ring size, chemical potential, and magnetic field.

Abstract

We have investigated the possible presence of Majorana fermions in a semiconductor quantum ring containing a few interacting electrons, and a strong spin-orbit interaction, proximity coupled to an s-wave superconductor. We have found that for rings with sizes of a few hundred angstroms and for certain values of the chemical potential and the entire range of the magnetic field, there are strong indications of the presence of Majorana fermions. In particular, the ground state energies and the average electron numbers for the states with even and odd electron numbers are almost identical. We have also studied the wave functions of Majorana fermions in the ring and have shown that Majorana fermions are well separated from each other in the angular coordinates. As he semiconductor quantum rings with a few interacting electrons are available in the laboratories, we believe that the long sought-after Majorana fermions could perhaps be unequivocally observed in such a system.