Superconductivity in undoped BaFe ₂ As ₂ by tetrahedral geometry design

Abstract

Significance The results demonstrated here show superconductivity in the antiferromagnetic BaFe 2 As 2 without chemical substitution, by atomic level control of local structure through epitaxial superlattice design. The interfacial interactions modify the FeAs 4 tetrahedra via systematic control of tetragonal and orthorhombic structures, inducing superconductivity. This indicates structure and dimensionality play an important role in the superconducting properties in Fe-based superconductors, and opens a path to structural manipulation of superconductivity in ultrathin layers of Fe-based materials. This is likely to play a major role in understanding and developing Fe-based superconductors.