Majorana transport in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings

TL;DR

This paper investigates Majorana fermion transport in superconducting nanowires with Rashba and Dresselhaus spin-orbit couplings, revealing conductance signatures, asymmetric currents, and phase transitions influenced by disorder and interactions.

Contribution

It introduces a comprehensive analysis of Majorana transport using Green functions, including effects of Coulomb interaction and disorder, and identifies conditions for topological phase transitions.

Findings

Zero-bias conductance peak indicates Majorana fermions.

Asymmetric currents due to hole transmission channels.

Topological phase transition influenced by disorder and superconductivity.

Abstract

Tunneling experiment is a key technique for detecting Majorana fermion in solid state systems. We use Keldysh non-equilibrium Green function method to study multi-lead tunneling in superconducting nanowire with Rashba and Dresselhaus spin-orbit couplings. A zero-bias \textit{dc} conductance peak appears in our setup which signifies the existence of Majorana fermion and is in accordance with previous experimental results on InSb nanowire. Interestingly, due to the exotic property of Majorana fermion, there exists a hole transmission channel which makes the currents asymmetric at the left and right leads. The \textit{ac} current response mediated by Majorana fermion is also studied here. To discuss the impacts of Coulomb interaction and disorder on the transport property of Majorana nanowire, we use the renormalization group method to study the phase diagram of the wire. It is found that there is a topological phase transition under the interplay of superconductivity and disorder. We find that the Majorana transport is preserved in the superconducting-dominated topological phase and destroyed in the disorder-dominated non-topological insulator phase.