Superconductivity at 22 K in Co-doped BaFe2As2 Crystals

TL;DR

This paper reports the discovery of bulk superconductivity at 22 K in Co-doped BaFe2As2 crystals, demonstrating electron doping as a new route to induce superconductivity in this family of materials.

Contribution

It is the first demonstration of superconductivity induced by electron doping in BaFe2As2, with detailed experimental and theoretical analysis.

Findings

Superconductivity observed below 22 K in Co-doped BaFe2As2

Electron doping introduces dominant electron carriers

Weak inter-band scattering due to Co doping

Abstract

Here we report bulk superconductivity in BaFe1.8Co0.2As2 single crystals below Tc = 22 K, as demonstrated by resistivity, magnetic susceptibility, and specific heat data. Hall data indicate that the dominant carriers are electrons, as expected from simple chemical reasoning. This is the first example of superconductivity induced by electron doping in this family of materials. In contrast to the cuprates, the BaFe2As2 system appears to tolerate considerable disorder in the FeAs planes. First principles calculations for BaFe1.8Co0.2As2 indicate the inter-band scattering due to Co is weak.