Dynamic response and electronic structure of potassium doped picene investigated by electron energy-loss spectroscopy

TL;DR

This study uses electron energy-loss spectroscopy to analyze how potassium doping affects the electronic structure and superconducting properties of picene, revealing new plasmon features and increased dielectric constant.

Contribution

It provides detailed insights into the electronic changes in potassium-doped picene, highlighting the emergence of charge carrier plasmons and band filling effects.

Findings

Appearance of a new plasmon peak in doped picene

Significant increase in dielectric constant upon doping

Filling of conduction bands with electrons

Abstract

We performed electron energy-loss spectroscopy studies in order to get a deeper insight into the electronic properties of potassium intercalated picene, a recently discovered superconductor. A comparison of the loss function of the undoped and doped compound shows the appearance of a new peak in the optical gap, which we attribute to the charge carrier plasmon. We find a dramatic increase for the value of the background dielectric constant $\epsilon_{\infty}$ upon doping. Our core level excitation data clearly signal filling of the conduction bands with electrons upon potassium addition.