Impurity states in altermagnetic superconductors

Abstract

Altermagnetic superconductors offer the possibility of exploring unconventional superconductivity, including topological states and finite-momentum superconductivity, with promising applications in spintronics and quantum information. However, a direct experimental confirmation of their existence remains elusive. In this work, we propose non-magnetic impurities as probes of the interplay between altermagnetism and superconductivity. These impurities induce spin-polarized subgap states whose spatial extension reflects the magnetic order of the substrate material. Depending on whether or not the impurity respects the bulk symmetries, these states form spin-degenerate or spin-split doublets. An external magnetic field aligned with the Néel vector can further control the doublet splitting. We further demonstrate that coupling between impurity states leads to a position-dependent, spin-sensitive hybridization, enabling another approach for \textit{in situ} control of atomic-size quantum devices. These findings provide unambiguous experimental signatures of altermagnetic superconductivity accessible via local measurements such as scanning tunneling microscopy and open unexplored pathways for designing tunable quantum devices.

10 pages, 8 figures

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Cited by in corpus (8)

• Light-induced Floquet spin-triplet Cooper pairs in unconventional magnets
• Unlocking Doping Effects on Altermagnetism in MnTe: Emergence of Quasi-altermagnetism
• Engineering subgap states in superconductors by the symmetry of altermagnetism
• Inverse proximity effect in thin-film superconductor/magnet heterostructures with metallic and insulating magnets
• Marginal Metals and Kosterlitz-Thouless Type Phase Transition in Disordered Altermagnets
• Altermagnetism from the viewpoint of chemistry
• Spin triplet pairing by suppressing altermagnetism
• Quantum Altermagnetic Instability in Disordered Metals