Local Superconductivity in Vanadium Iron Arsenide

TL;DR

This study explores how substituting group 5 elements into BaFe2As2 affects its structure and superconductivity, revealing local superconducting regions despite the absence of bulk superconductivity.

Contribution

It uncovers the coexistence of local superconductivity and antiferromagnetism in V-doped BaFe2As2, a novel observation in transition-metal hole-doped iron arsenides.

Findings

V substitution increases c-lattice parameter

Local superconducting regions coexist with antiferromagnetism

Bulk superconductivity is absent despite local superconductivity

Abstract

We investigate the chemical substitution of group 5 into BaFe2As2 (122) iron arsenide, in the effort to understand why Fe-site hole doping of this compound (e.g., using group 5 or 6) does not yield bulk superconductivity. We find an increase in c-lattice parameter of the BaFe2As2 with the substitution of V, Nb, or Ta; the reduction in c predicts the lack of bulk superconductivity [1] that is confirmed here through transport and magnetization results. However, our spectroscopy measurements find a coexistence of antiferromagnetic and local superconducting nanoscale regions in V-122, observed for the first time in a transition-metal hole-doped iron arsenide. In BaFe2As2, there is a complex connection between local parameters such as composition and lattice strain, average lattice details, and the emergence of bulk quantum states such as superconductivity and magnetism. [1] L. M. N. Konzen, and A. S. Sefat, J. Phys.: Condens. Matter 29 (2017), 083001.