Testing the topological nature of end states in antiferromagnetic atomic chains on superconductors

Abstract

Edge states forming at the boundaries of topologically non-trivial phases of matter are promising candidates for future device applications because of their stability against local perturbations. Magnetically ordered spin chains proximitized by an s-wave superconductor are predicted to enter a topologically non-trivial mini-gapped phase with zero-energy Majorana modes (MMs) localized at their ends. However, the presence of non-topological end states mimicking MM properties can spoil their unambiguous observation. Here, we report on a method to experimentally decide on the MM nature of end states observed for the first time in antiferromagnetic spin chains. Using scanning tunneling spectroscopy, we find end states at either finite or near-zero energy in Mn chains on Nb(110) or Ta(110), respectively, within a large minigap. By introducing a locally perturbing defect on one end of the chain, the end state on this side splits off from zero-energy while the one on the other side doesn't - ruling out their MM origin. A minimal model shows that, while wide trivial minigaps hosting such conventional end states are easily achieved in antiferromagnetic spin chains, unrealistically large spin-orbit couplings are required to drive the system into the topologically nontrivial phase with MMs. The methodology of perturbing chains by local defects is a powerful tool to probe the stability of future candidate topological edge modes against local disorder.

References in corpus (46)

• Unpaired Majorana fermions in quantum wires
• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Majorana fermions in chains of magnetic atoms on a superconductor
• Topological Superconductivity and Majorana Fermions in RKKY Systems
• Topological superconducting phase in helical Shiba chains
• Topological superconductivity in a van der Waals heterostructure
• End states and subgap structure in proximity-coupled chains of magnetic adatoms
• High-resolution studies of the Majorana atomic chain platform
• Unconventional pairing in the iron arsenide superconductors
• Single magnetic adsorbates on s-wave superconductors
• Atomic-Scale Interface Engineering of Majorana Edge Modes in a 2D Magnet-Superconductor Hybrid System
• Topological Superconductivity induced by Ferromagnetic Metal Chains
• A novel platform for two-dimensional chiral topological superconductivity
• Strong localization of Majorana end states in chains of magnetic adatoms
• Unconventional topological phase transitions in helical Shiba chains
• Exploring a proximity-coupled Co chain on Pb(110) as a possible Majorana platform
• Orbital Picture of Yu-Shiba-Rusinov Multiplets
• Topological Yu-Shiba-Rusinov chain from spin-orbit coupling
• Evidence of topological Shiba bands in artificial spin chains on superconductors
• Majorana fermions from Shiba states in an antiferromagnetic chain on top of a superconductor
• Controlled length-dependent interaction of Majorana modes in Yu-Shiba-Rusinov chains
• Wave-function hybridization in Yu-Shiba-Rusinov dimers
• Self-Organized Topological Superconductivity in a Yu-Shiba-Rusinov Chain
• Probing magnetic interactions between Cr adatoms on the $\beta$-Bi${}_2$Pd superconductor
• Tuning emergent magnetism in a Hund's impurity
• Evidence for interfacial superconductivity in a bi-collinear antiferromagnetically ordered FeTe monolayer on a topological insulator
• Interplay of topological phases in magnetic adatom-chains on top of a Rashba superconducting surface
• Spin-orbit coupling induced splitting of Yu-Shiba-Rusinov states in antiferromagnetic dimers
• Atomic-scale spin-polarization maps using functionalized superconducting probes
• Yu-Shiba-Rusinov states in the charge-density modulated superconductor NbSe2
• Quantum spins and hybridization in artificially-constructed chains of magnetic adatoms on a superconductor
• Controlling in-gap end states by linking nonmagnetic atoms and artificially-constructed spin chains on superconductors
• On the preparation and electronic properties of clean superconducting Nb(110) surfaces
• Impurity-induced bound states in superconductors with spin-orbit coupling
• Observation of tunable single-atom Yu-Shiba-Rusinov states
• Non-Majorana modes in diluted spin chains proximitized to a superconductor
• Chern mosaic - topology of chiral superconductivity on ferromagnetic adatom lattices
• Majorana Bound States Induced by Antiferromagnetic Skyrmion Textures
• Atomic Manipulation of In-gap States on the $\beta$-Bi${}_2$Pd Superconductor
• Coexistence of Antiferromagnetism and Superconductivity in Mn/Nb(110)
• Relativistic first principles theory of Yu--Shiba--Rusinov states applied to an Mn adatom and Mn dimers on Nb(110)
• Majorana bound states in a superconducting Rashba nanowire in the presence of antiferromagnetic order
• Systematic study of Mn atoms, artificial dimers and chains on superconducting Ta(110)
• Increased localization of Majorana modes in antiferromagnetic chains on superconductors
• Atomic-scale coexistence of short-range magnetic order and superconductivity in Fe${}_{1+y}$Se${}_{0.1}$Te${}_{0.9}$
• Moiré dispersion of edge states in spin chains on superconductors

Cited by in corpus (10)

• Majorana quasiparticles in atomic spin chains on superconductors
• Observation of Yu-Shiba-Rusinov-like states at the edge of CrBr3/NbSe2 heterostructure
• Controlling Majorana hybridization in magnetic chain-superconductor systems
• Emergence of Exotic Spin Texture in Supramolecular Metal Complexes on a 2D Superconductor
• Fractional Spin Quantum Hall Effect in Weakly Coupled Spin Chain Arrays
• Magnetic flux induced topological superconductivity in magnetic atomic rings
• Magnetic flux induced higher-order topological superconductivity
• The feedback driven atomic scale Josephson microscope
• Direct signatures of $d$-level hybridization and dimerization in magnetic adatom chains on a superconductor
• Nonreciprocal Equilibrium Josephson Effect of Arbitrary Periodicity from Poor Man's Majorana Zero Modes