Disentangling Majorana fermions from conventional zero energy states in semiconductor quantum wires

Abstract

Majorana fermions (MFs) are predicted to occur as zero-energy bound states in semiconductor nanowire-superconductor structures. However, in the presence of disorder or smooth confining potentials, these structures can also host non-topological nearly-zero energy states. Here, we demonstrate that the MFs and the nearly-zero topologically-trivial states have different characteristic signatures in a tunneling conductance measurement, which allows to clearly discriminate between them. We also show that low-energy non-topological states can strongly hybridize with metallic states from the leads, which generates the smooth background that characterizes the soft superconducting gap measured in tunneling experiments and produces an additional decoherence mechanism for the Majorana mode. Our results pave the way for the conclusive identification of MFs in a solid state system and provide directions for minimizing quantum decoherence in Majorana wires.

4+ pages, 5 figures; the issue of soft superconducting gap emphasized; version as published

References in corpus (10)

• Superconducting proximity effect and Majorana fermions at the surface of a topological insulator
• 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
• Non-Abelian Topological Order in S-Wave Superfluids of Ultracold Fermionic Atoms
• Non-Abelian quantum order in spin-orbit-coupled semiconductors: The search for topological Majorana particles in solid state systems
• $p_x+i{p}_y$ superfluid from s-wave interactions of fermionic cold atoms
• Observing Majorana Bound States in p-wave Superconductors Using Noise Measurements in Tunneling Experiments
• To close or not to close: the fate of the superconducting gap across the topological quantum phase transition in Majorana-carrying semiconductor nanowires

Cited by in corpus (13)

• Majorana nanowires for topological quantum computation
• Weak measurement protocols for Majorana bound state identification
• Numerical study of PbTe-Pb hybrid nanowires for engineering Majorana zero modes
• Recent progress on Majorana in semiconductor-superconductor heterostructures--Engineering and detection
• Majorana/Andreev crossover and the fate of the topological phase transition in inhomogeneous nanowires
• Time-delay matrix, midgap spectral peak, and thermopower of an Andreev billiard
• Phenomenology of Majorana zero modes in full-shell hybrid nanowires
• 1D Majorana Goldstinos and partial supersymmetry breaking in quantum wires
• Dispersive 1D Majorana modes with emergent supersymmetry in 1D proximitized superconductors via spatially-modulated potentials and magnetic fields
• Assessing bound states in a one-dimensional topological superconductor: Majorana versus Tamm
• Topological zero modes and bounded modes at smooth domain walls: Exact solutions and dualities
• Effects of the Vertices on the Topological Bound States in a Quasicrystalline Topological Insulator
• Zero energy modes with Gaussian, exponential, or polynomial decay: Exact solutions in hermitian and nonhermitian regimes