# Shifts and Splittings of the Hole Bands in the Nematic Phase of FeSe

## TL;DR

This study uses laser-ARPES to investigate how the hole-like bands in FeSe change across the nematic transition, revealing significant band splittings and shifts that clarify the electronic structure in the nematic phase.

## Contribution

The paper provides detailed measurements of band shifts and splittings in FeSe's nematic phase, offering new insights into the electronic structure changes at the transition.

## Key findings

- 13 meV increase in $d_{xz}$/$d_{yz}$ band splitting at 90 K
- 10 meV downward shift of the $d_{xy}$ band at 90 K
- Clarifies the temperature-dependent band behavior in FeSe's nematic phase

## Abstract

We report a high-resolution laser-based angle-resolved photoemission spectroscopy (laser-ARPES) study of single crystals of FeSe, focusing on the temperature-dependence of the hole-like bands around the ${\rm \Gamma}$ point. As the system cools through the tetragonal-orthorhombic "nematic" structural transition at 90~K, the splitting of the $d_{xz}$/$d_{yz}$ bands is observed to increase by a magnitude of 13 meV. Moreover, the onset of a $\sim$10 meV downward shift of the $d_{xy}$ band is also at 90~K. These measurements provide clarity on the nature, magnitude and temperature-dependence of the band shifts at the ${\rm \Gamma}$ point in the nematic phase of FeSe.