Electronic structure reconstruction: the driving force behind the magnetic and structural transitions in NaFeAs

TL;DR

This study uses angle-resolved photoemission spectroscopy to show that in NaFeAs, electronic structure changes drive both structural and magnetic transitions, challenging the Fermi surface nesting explanation.

Contribution

It provides direct experimental evidence that electronic structure reconstruction, not Fermi surface nesting, causes structural and magnetic transitions in Fe-based superconductors.

Findings

Electronic band shifts occur around the structural transition temperature.

Band folding appears with magnetic order around the structural transition.

Electronic structure reconstruction drives both transitions.

Abstract

The electronic structure of NaFeAs is studied with angle resolved photoemission spectroscopy on high quality single crystals. Large portions of the band structure start to shift around the structural transition temperature, and smoothly evolve as the temperature lowers through the spin density wave transition. Moreover, band folding due to magnetic order emerges around structural transition. Our observation provides direct evidence that the structural and magnetic transitions share the same origin, and are both driven by the electronic structure reconstruction in Fe-based superconductors, instead of Fermi surface nesting.