Coexistence of Dirac-Cone States and Superconductivity in Iron Pnictide Ba(Fe$_{1-x}$Ru$_x$As)$_2$

TL;DR

This study investigates how Ru doping affects Dirac cone states in Ba(Fe$_{1-x}$Ru$_x$As)$_2$ superconductors, revealing that Dirac states coexist with antiferromagnetism and superconductivity, with magnetoresistance measurements supporting their persistence.

Contribution

It provides experimental evidence that Dirac cone states persist in the coexistence region of antiferromagnetism and superconductivity in Ru-doped BaFeAs, using magnetoresistance analysis.

Findings

Linear magnetoresistance observed at low temperatures for various Ru doping levels.

Magnetoresistance explained by quantum limit of Dirac cone states.

Dirac cone states coexist with antiferromagnetic and superconducting phases.

Abstract

The Ru doping effect on the Dirac cone states is investigated in iron pnictide superconductors Ba(Fe$_{1-x}$Ru$_x$As)$_2$ using the transverse magnetoresistance (MR) measurements as a function of temperature. The linear development of MR against magnetic field $B$ is observed for $x$ = 0 - 0.244 at low temperatures below the antiferromagnetic transition. The $B$-linear MR is interpreted in terms of the quantum limit of the Dirac cone states by using the model proposed by Abrikosov. An intriguing evidence is shown that the Dirac cone state persists on the electronic phase diagram where the antiferromagnetism and the superconductivity coexist.