Tunable superconductivity in Fe-pnictide heterointerfaces by diffusion control

Abstract

New Fe-pnictide heterostructures of the type LnOFeAs/BaFe${}_2$As${}_2$ (Ln = La, Sm) were grown by pulsed laser deposition (PLD) and investigated. Their common structural unit of [Fe${}_2$As${}_2$] planes allows perfect matching between the different Fe-pnictide unit cells and a coherent and atomically sharp interface. We test the stability of the heterointerface in the presence of Co${}^{2+}$ (cations) as well as for excess O${}^{2-}$ (anions) and discuss the consequences on the electronic properties: While undoped SmOFeAs/BaFe${}_2$As${}_2$ remains non-superconducting, a balanced Co-concentration after diffusion across the interface results in superconductivity within Co-substituted variants. In contrast, excess O${}^{2-}$ causes the formation of an interfacial layer in SmOFeAs/BaFe${}_2$As${}_2$ with increased O${}^{2-}$/As${}^{3-}$ ratio and develops a metal-to-superconductor transition with time. The engineered heterointerfaces may provide a sophisticated pathway to bridge the gap between Fe-pnictides and Fe-chalcogenides.

arXiv comment19 pages, 5 figures

References in corpus (16)

• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3
• Phase Diagram and High Temperature Superconductivity at 65 K in Tuning Carrier Concentration of Single-Layer FeSe Films
• Interface-induced superconductivity and strain-dependent spin density wave in FeSe/SrTiO3 thin films
• Effect of Co doping on superconductivity and transport properties in SmFe${}_{1-x}$Co${}_x$AsO
• Superconductivity induced by cobalt doping in iron-based oxyarsenides
• Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3(110)
• Monolayer FeSe on SrTiO${}_3$
• Artificially engineered superlattices of pnictide superconductor
• Scaling behaviour of the critical current in clean epitaxial Ba(Fe1-xCox)2As2 thin films
• A perspective on pnictide superconductors
• Coherent interfacial bonding on the FeAs tetrahedron in Fe/Ba(Fe(1-x)Co(x))2As2 bilayers
• Fast Pixelated Detectors in Scanning Transmission Electron Microscopy. Part II: Post Acquisition Data Processing, Visualisation, and Structural Characterisation
• Artificial and self-assembled pinning centers in Ba(Fe1-xCox)2As2 thin films as a route to very high current density
• Identical effects of indirect and direct electron doping of superconducting BaFe2As2 thin films
• Superconductivity in Undoped BaFe2As2 by Tetrahedral Geometry Design
• Surface reconstruction and charge modulation in BaFe2As2 superconducting film