Tunneling conductance in semiconductor-superconductor hybrid structures

Abstract

We study the differential conductance for charge tunneling into a semiconductor wire--superconductor hybrid structure, which is actively investigated as a possible scheme for realizing topological superconductivity and Majorana zero modes. The calculations are done based on a tight-binding model of the heterostructure using both a Blonder-Tinkham-Klapwijk approach and a Keldysh non-equilibrium Green's function method. The dependence of various tunneling conductance features on the coupling strength between the semiconductor and the superconductor, the tunnel barrier height, and temperature is systematically investigated. We find that treating the parent superconductor as an active component of the system, rather than a passive source of Cooper pairs, has qualitative consequences regarding the low-energy behavior of the differential conductance. In particular, the presence of sub-gap states in the parent superconductor, due to disorder and finite magnetic fields, leads to characteristic particle-hole asymmetric features and to the breakdown of the quantization of the zero-bias peak associated with the presence of Majorana zero modes localized at the ends of the wire. The implications of these findings for the effort toward the realization of Majorana bound states with true non-Abelian properties are discussed.

published version, 15+ pages, 12 figures

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Cited by in corpus (12)

• Physical mechanisms for zero-bias conductance peaks in Majorana nanowires
• Experimental Phase Diagram of a One-Dimensional Topological Superconductor
• On controlling the bound states in quantum-dot hybrid-nanowire
• Zero-energy pinning of topologically-trivial bound states in multi-band semiconductor-superconductor nanowires
• Robust low-energy Andreev bound states in semiconductor-superconductor heterostructures: Importance of partial separation of component Majorana bound states
• Charge impurity effects in hybrid Majorana nanowires
• Conductance feature smearing and anisotropic suppression of induced superconductivity in a Majorana nanowire
• Majorana bound states in a superconducting Rashba nanowire in the presence of antiferromagnetic order
• Control and detection of Majorana bound states in quantum dot arrays
• Signatures of the Majorana spin in electrical transport through a Majorana nanowire
• Electrostatical formation of the Majorana quasiparticles in the quantum dot--nanoring structure
• Majorana Bound State leakage to impurity in Su-Schrieffer-Heeger-Rashba scenario