The Microstrain-Doping Phase Diagram of the Iron Pnictides Heterostructures at Atomic Limit

TL;DR

This paper proposes a 3D phase diagram for iron pnictides, showing how charge density and microstrain influence superconductivity, and identifies conditions for maximizing critical temperature in FeAs-based heterostructures.

Contribution

It introduces a novel phase diagram linking microstrain and doping to superconductivity in iron pnictides, emphasizing the atomic-limit heterostructure nature of these materials.

Findings

Critical microstrain range enhances Tc

FeAs layers exhibit tensile microstrain due to misfit

Optimal doping and strain conditions maximize superconductivity

Abstract

The 3D phase diagram of iron pnictides where the critical temperature depends on charge density and microstrain in the active FeAs layers is proposed. The iron pnictides superconductors are shown to be a practical realization of a heterostructure at the atomic limit made of a superlattice of FeAs layers intercalated by spacer layers. We have focussed our interest on the A 1-x BxFe2As2 (122) families and we show that FeAs layers have a tensile microstrain due to the misfit strain between the active layers and the spacers. We have identified the critical range of doping and microstrain where the critical temperature gets amplified to its maximum value.