K_{z} Selective Scattering within Quasiparticle Interference Measurements of FeSe.

Luke C Rhodes,Matthew D Watson,Timur K Kim,Matthias Eschrig

doi:10.1103/physrevlett.123.216404

Abstract

Quasiparticle interference (QPI) provides a wealth of information relating to the electronic structure of a material. However, it is often assumed that this information is constrained to two-dimensional electronic states. We show that this is not necessarily the case. For FeSe, a system dominated by surface defects, we show that it is actually all electronic states with negligible group velocity in the z axis that are contained within the experimental data. By using a three-dimensional tight-binding model of FeSe, fit to photoemission measurements, we directly reproduce the experimental QPI scattering dispersion, within a T-matrix formalism, by including both k_{z}=0 and k_{z}=π electronic states. This result unifies both tunnelling based and photoemission based experiments on FeSe and highlights the importance of k_{z} within surface sensitive measurements of QPI.

Highlights

The iron-based superconductor FeSe has recently been a focal point in the study of unconventional superconductivity
In order to resolve the differences in theoretical models of the electronic structure, it is important to study the results and conclusions extracted from experimental measurements, such as angle-resolved photoemission spectroscopy (ARPES) and Quasiparticle interference (QPI)
QPI measurements of FeSe [7,12,13], obtained via scanning tunneling microscopy (STM), have been interpreted as being consistent with a theoretical model where the Fermi surface consists of one hole pocket and two electron pockets and exhibits a large difference in the quasiparticle weight of the dxz and dyz orbitals [13]

Summary

Introduction

The iron-based superconductor FeSe has recently been a focal point in the study of unconventional superconductivity. By using a three-dimensional tight-binding model of FeSe, fit to photoemission measurements, we directly reproduce the experimental QPI scattering dispersion, within a T-matrix formalism, by including both kz 1⁄4 0 and kz 1⁄4 π electronic states.

Results

Conclusion