Zero-energy bound states in the high-temperature superconductors at the two-dimensional limit

Abstract

Majorana zero modes (MZMs) that obey the non-Abelian statistics have been intensively investigated for potential applications in topological quantum computing. The prevailing signals in tunneling experiments "fingerprinting" the existence of MZMs are the zero-energy bound states (ZEBSs). However, nearly all of the previously reported ZEBSs showing signatures of the MZMs are observed in difficult-to-fabricate heterostructures at very low temperatures and additionally require applied magnetic field. Here, by using in-situ scanning tunneling spectroscopy, we detect the ZEBSs upon the interstitial Fe adatoms deposited on two different high-temperature superconducting one-unit-cell-thick iron chalcogenides on SrTiO3(001). The spectroscopic results resemble the phenomenological characteristics of the MZMs inside the vortex cores of topological superconductors. Our experimental findings may extend the MZM explorations in connate topological superconductors towards an applicable temperature regime and down to the two-dimensional limit. While a concrete understanding of the observations is lacking, possible explanations involving novel 2D superconducting states with spin-orbit coupling, spontaneous nucleation of anomalous vortices at the magnetic sites, and noncoplanar magnetic ordering may further stimulate theoretical understandings of the scarcely captured ZEBSs in strongly correlated systems with multiband Cooper pairing.

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Cited by in corpus (16)

• On the Remarkable Superconductivity of FeSe and its Close Cousins
• Visualization of Topological Boundary Modes Manifesting Topological Nodal-Point Superconductivity
• Discovery of a pair density wave state in a monolayer high-Tc iron-based superconductor
• A comprehensive review on topological superconducting materials and interfaces
• Phase-manipulation-induced Majorana Mode and Braiding Realization in Iron-based Superconductor Fe(Te,Se)
• Emergent vortex Majorana zero mode in iron-based superconductors
• Experimental review on Majorana zero-modes in hybrid nanowires
• Doping-induced superconductivity in the topological semimetal Mo5Si3
• Direct probing of a large spin-orbit coupling in the FeSe superconducting monolayer on STO: Evidence for nontrivial topological states
• Ferromagnetic Impurity Induced Majorana Zero Mode in Iron-Based Superconductor
• Evidence for a robust sign-changing s-wave order parameter in monolayer films of superconducting Fe (Se,Te)/Bi2Te3
• Pairing symmetry in monolayer of orthorhombic CoSb
• Capping layer influence and isotropic in-plane upper critical field of the superconductivity at the FeSe/SrTiO3 interface
• Robust topological state against magnetic impurities observed in superconductor PbTaSe2
• Spectroscopic evidence of disorder-induced quantum phase transitions in monolayer Fe(Te,Se) superconductor
• A mesoscopic device for a realization of the Topological Kondo effect