Effect of nematic ordering on electronic structure of FeSe

TL;DR

This study uses experimental and computational methods to clarify how nematic order influences the electronic structure of FeSe, providing key insights into its role in high-temperature superconductivity.

Contribution

It offers the first precise measurement of the energy and momentum scales of nematic order in FeSe, confirming its electronic origin and resolving recent controversies.

Findings

Nematicity in FeSe is electronically driven.

Quantitative energy and momentum scales of nematic order are identified.

Results support theories incorporating spin-orbit interaction and nematicity.

Abstract

Electronically driven nematic order is often considered as an essential ingredient of high-temperature superconductivity. Its elusive nature in iron-based supercon- ductors resulted in a controversy not only as regards its origin but also as to the degree of its influence on the electronic structure even in the simplest representative material FeSe. Here we utilized angle-resolved photoemission spectroscopy and density functional theory calculations to study the influence of the nematic order on the electronic structure of FeSe and determine its exact energy and momentum scales. Our results strongly suggest that the nematicity in FeSe is electronically driven, we resolve the recent controversy and provide the necessary quantitative experimental basis for a successful theory of superconductivity in iron-based materials which takes into account both, spin-orbit interaction and electronic nematicity.