New Fe-pnictide heterostructures of the type LnOFeAs/BaFe2As2 (Ln = La, Sm) were grown by pulsed laser deposition (PLD) and investigated. Their common structural unit of [Fe2As2] planes allows perfect matching between the different Fe-pnictide unit cells and a coherent and atomically sharp interface. We test the stability of the heterointerface in the presence of Co2+ (cations) as well as for excess O2− (anions) and discuss the consequences on the electronic properties: While undoped SmOFeAs/BaFe2As2 remains non-superconducting, a balanced Co-concentration after diffusion across the interface results in superconductivity within Co-substituted variants. In contrast, excess O2− causes the formation of an interfacial layer in SmOFeAs/BaFe2As2 with increased O2−/As3− ratio and develops a metal-to-superconductor transition with time. The engineered heterointerfaces may provide a sophisticated pathway to bridge the gap between Fe-pnictides and Fe-chalcogenides.
@article{arxiv.2009.04799,
title = {Tunable superconductivity in Fe-pnictide heterointerfaces by diffusion control},
author = {Silvia Haindl and Sergey Nikolaev and Michiko Sato and Masato Sasase and Ian MacLaren},
journal= {arXiv preprint arXiv:2009.04799},
year = {2021}
}