Majorana versus Andreev bound state energy oscillations in a 1D semiconductor-superconductor heterostructure

Abstract

The recent experimental observations of decaying energy oscillations in semiconductor-superconductor Majorana nanowires is in contrast with the typical expectations based on the presence of Majorana zero modes localized at the ends of the system, when the amplitude of the hybridization energy oscillations is predicted to increase with the applied magnetic field. These observations have been theoretically justified recently by considering a position-dependent, step-like spin-orbit coupling near end of the nanowire, which could arise due to the presence of tunnel gates in a standard tunneling conductance experiment. Here, we show that the window in parameter space where this phenomenology occurs is vanishingly small, when compared to the parameter region where Majorana oscillations increase in amplitude with the applied field. Further, including a position-dependent effective potential, which is also induced naturally near the end of the wire by, e.g., tunnel gates, practically removes the small window associated with decaying oscillations. Using extensive numerical calculations, we show that, as expected, increasing amplitude oscillations of the hybridization energy represent a generic property of topological Majorana zero modes, while decreasing amplitude oscillations are a generic property of low-energy trivial Andreev bound states that typically emerge in non-homogeneous systems. By averaging over several realistic parameter configurations, we identify robust features of the hybridization energy that can be observed in a typical differential conductance experiment without fine-tuning the control parameters.

12 pages, 7 figures

References in corpus (20)

• Non-Abelian Anyons and Topological Quantum Computation
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Majorana Fermions and a Topological Phase Transition in Semiconductor-Superconductor Heterostructures
• Evidence of Majorana fermions in an Al - InAs nanowire topological superconductor
• Observation of Majorana Fermions in a Nb-InSb Nanowire-Nb Hybrid Quantum Device
• Majorana bound states in a coupled quantum-dot hybrid-nanowire system
• Anomalous modulation of a zero bias peak in a hybrid nanowire-superconductor device
• Non-Abelian quantum order in spin-orbit-coupled semiconductors: The search for topological Majorana particles in solid state systems
• Scaling of Majorana Zero-Bias Conductance Peaks
• Transport spectroscopy of NS nanowire junctions with Majorana fermions
• Towards a realistic transport modeling in a superconducting nanowire with Majorana fermions
• A Majorana smoking gun for the superconductor-semiconductor hybrid topological system
• Ballistic superconductivity in semiconductor nanowires
• SNS junctions in nanowires with spin-orbit coupling: role of confinement and helicity on the sub-gap spectrum
• Splitting of Majorana modes due to intervortex tunneling in a p + ip superconductor
• Majorana splitting from critical currents in Josephson junctions
• Zero bias conductance peak in Majorana wires made of semiconductor-superconductor hybrid structures
• On controlling the bound states in quantum-dot hybrid-nanowire
• Mutation of Andreev into Majorana bound states in long NS and SNS junctions
• Fermionic and Majorana Bound States in Hybrid Nanowires with Non-Uniform Spin-Orbit Interaction

Cited by in corpus (7)

• Majorana nanowires for topological quantum computation
• Partially-separated Majorana modes in a disordered medium
• Majorana/Andreev crossover and the fate of the topological phase transition in inhomogeneous nanowires
• Full parity phase diagram of a proximitized nanowire island
• Feasibility of measurement-based braiding in the quasi-Majorana regime of semiconductor-superconductor heterostructures
• Majorana polarization in disordered heterostructures
• Majorana modes in graphene strips: polarization, wavefunctions, disorder, and Andreev states