Crystal Chemistry and Structural Design of Iron-Based Superconductors

TL;DR

This paper reviews the crystal chemistry of iron-based high-temperature superconductors and proposes a rational structural design approach for discovering new materials based on HSAB concepts.

Contribution

It provides a comprehensive review of known iron-based superconductors and introduces a novel design strategy for future material exploration.

Findings

Summarized the crystal chemistry of iron-based superconductors.

Proposed an alternative structural design route for new superconductors.

Abstract

The second class of high-temperature superconductors (HTSCs), iron-based pnictides and chalcogenides, necessarily contain Fe$_2$$X_2$ ("$X$" refers to a pnictogen or a chalcogen element) layers, just like the first class of HTSCs which possess the essential CuO$_2$ sheets. So far, dozens of iron-based HTSCs, classified into nine groups, have been discovered. In this article, the crystal-chemistry aspects of the known iron-based superconductors are reviewed and summarized by employing "hard and soft acids and bases (HSAB)" concept. Based on these understandings, we propose an alternative route to exploring new iron-based superconductors via rational structural design.