Electronic reconstruction through the structural and magnetic transitions in detwinned NaFeAs

TL;DR

This study uses ARPES to investigate electronic changes in NaFeAs across structural and magnetic transitions, revealing orbital anisotropy and band folding linked to nematic and antiferromagnetic phases, suggesting a common behavior in iron pnictides.

Contribution

It provides detailed insights into the electronic reconstruction and orbital anisotropy at structural and magnetic transitions in NaFeAs, highlighting their role in nematic phases.

Findings

Orbital anisotropy develops rapidly at the structural transition.

Band folding occurs at the magnetic transition.

Electronic reconstruction behaviors are similar in NaFeAs and Ba(Fe1-xCox)2As2.

Abstract

We use angle-resolved photoemission spectroscopy to study twinned and detwinned iron pnictide compound NaFeAs. Distinct signatures of electronic reconstruction are observed to occur at the structural (TS) and magnetic (TSDW) transitions. At TS, C4 rotational symmetry is broken in the form of an anisotropic shift of the orthogonal dxz and dyz bands. The magnitude of this orbital anisotropy rapidly develops to near completion upon approaching TSDW, at which temperature band folding occurs via the antiferromagnetic ordering wave vector. Interestingly, the anisotropic band shift onsetting at TS develops in such a way to enhance the nesting conditions in the C2 symmetric state, hence is intimately correlated with the long range collinear AFM order. Furthermore, the similar behaviors of the electronic reconstruction in NaFeAs and Ba(Fe1-xCox)2As2 suggests that this rapid development of large orbital anisotropy between TS and TSDW is likely a general feature of the electronic nematic phase in the iron pnictides, and the associated orbital fluctuations may play an important role in determining the ground state properties.