Structural distortion as prerequisite for superconductivity in LiFeAs

TL;DR

This paper proposes that a structural distortion in LiFeAs, caused by iron atom displacement, is essential for its superconductivity, as predicted by a nonadiabatic Heisenberg model and group-theoretical analysis.

Contribution

It introduces a theoretical model linking structural distortion to superconductivity in LiFeAs, highlighting the role of symmetry reduction and atomic displacement.

Findings

Structural distortion occurs above or at the superconducting transition temperature.

Displacement of iron atoms reduces symmetry, enabling superconductivity.

The nonadiabatic Heisenberg model predicts this distortion as a prerequisite.

Abstract

The nonadiabatic Heisenberg model predicts a structural distortion in LiFeAs below a temperature higher than (or at least equal to) the superconducting transition temperature. Within this group-theoretical model, the reduction of the symmetry caused by the distortion is a prerequisite for the superconducting state in this compound and can be realized by a mere displacement of the iron atoms from their positions in the space group P4/nmm.