Heavy anion solvation of polarity fluctuations in Pnictides

TL;DR

This paper discusses the unique physical properties of iron-pnictide superconductors, emphasizing the role of large pnictide polarizabilities in their structural and electronic behavior, which differentiates them from cuprates.

Contribution

It highlights the significance of heavy anion solvation and polarity fluctuations in understanding the properties of iron-pnictide superconductors, proposing a new perspective distinct from cuprate theories.

Findings

Large pnictide polarizabilities dominate the properties of Fe-based superconductors.

The physical paradigm of iron-pnictides differs fundamentally from cuprates.

Polarity fluctuations are key to understanding their high-temperature superconductivity.

Abstract

Once again the condensed matter world has been surprised by the discovery of yet another class of high temperature superconductors. The discovery of iron-pnictide (FeAs) and chalcogenide (FeSe) based superconductors with a $T_c$ of up to 55 K is again evidence of how complex the many body problem really is, or in another view how resourceful nature is. The first reactions would of course be that these new materials must in some way be related to the copper-oxide based superconductors for which a large number of theories exist although a general consensus regarding the correct theory has not yet been reached. Here we point out that the basic physical paradigm of the new iron based superconductors is entirely different from the cuprates. Their fundamental properties, structural and electronic, are dominated by the exceptionally large pnictide polarizabilities.