Effect of the sample work function on alkali metal dosing induced electronic structure change

TL;DR

This study investigates how the initial work function of materials influences the electronic structure changes induced by alkali metal dosing, revealing a proportional relationship useful for predicting doping effects.

Contribution

It demonstrates a correlation between sample work function and electronic structure change upon alkali metal dosing in iron-based superconductors, offering a predictive approach.

Findings

Electronic structure change is proportional to work function difference.

Work function can estimate doping-induced electronic modifications.

Results apply to multiple iron-based superconductors.

Abstract

Alkali metal dosing (AMD) has been widely used as a way to control doping without chemical substitution. This technique, in combination with angle resolved photoemission spectroscopy (ARPES), often provides an opportunity to observe unexpected phenomena. However, the amount of transferred charge and the corresponding change in the electronic structure vary significantly depending on the material. Here, we report study on the correlation between the sample work function and alkali metal induced electronic structure change for three iron-based superconductors: FeSe, Ba(Fe$_{0.94}$Co$_{0.06}$)$_{2}$As$_{2}$ and NaFeAs which share a similar Fermi surface topology. Electronic structure change upon monolayer of alkali metal dosing and the sample work function were measured by ARPES. Our results show that the degree of electronic structure change is proportional to the difference between the work function of the sample and Mulliken's absolute electronegativity of the dosed alkali metal. This finding provides a possible way to estimate the AMD induced electronic structure change.