Near zero-energy Caroli-de Gennes-Matricon vortex states in the presence of impurities

Abstract

Caroli-de Gennes-Matricon (CdGM) states are localized states with a discrete energy spectrum bound to the core of vortices in superconductors. In topological superconductors, CdGM states are predicted to coexist with zero-energy, chargeless states widely known as Majorana zero modes (MZMs). Due to their energy difference, current experiments rely on scanning tunneling spectroscopy methods to distinguish between them. This work shows that electrostatic inhomogeneities can push trivial CdGM states arbitrarily close to zero energy in non-topological systems where no MZM is present. Furthermore, the BCS charge of CdGM states is suppressed under the same mechanism. Through exploration of the impurity parameter space, we establish that these two phenomena generally happen in consonance. Our results show that energy and charge shifts in CdGM may be enough to imitate the spectroscopic signatures of MZMs even in cases where the estimated CdGM level spacing (in the absence of impurities) is much larger than the typical experimental level broadening.

Revised and expanded version. 8 pages, 5 figures

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Cited by in corpus (14)

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• Non-Hermitian zero-energy pinning of Andreev and Majorana bound states in superconductor-semiconductor systems
• Entanglement measures of Majorana bound states
• Revealing the Microscopic Mechanism of Elementary Vortex Pinning in Superconductors
• Differential current noise as an identifier of Andreev bound states that induce nearly quantized conductance plateaus
• Odd-frequency pairing due to Majorana and trivial Andreev bound states
• Anomalous proximity effect under Andreev and Majorana bound states
• Detection of Majorana zero modes bound to Josephson vortices in planar superconductor-topological insulator-superconductor junctions
• Unveiling In-Gap States and Majorana Zero Modes in Superconductor-Topological Insulator Bilayer model
• Quantum interference among vortex bound states in superconductors
• Odd-frequency Pairing in Josephson Junctions Coupled by Magnetic Textures