Quasiperiodic free electron metal layers

TL;DR

This study demonstrates that alkali metal monolayers on icosahedral surfaces form quasiperiodic structures without a pseudogap at the Fermi level, combining experimental and theoretical approaches.

Contribution

It provides the first detailed analysis of quasiperiodic alkali metal layers on quasicrystalline surfaces using electron diffraction, spectroscopy, and density functional theory.

Findings

Alkali metal monolayers form quasiperiodic structures on icosahedral surfaces.

The quasiperiodicity extends to the second layer in sodium.

No pseudogap near the Fermi level in the alkali metal adlayer.

Abstract

Using electron diffraction, we show that free electron metals such as sodium and potassium form a highly regular quasiperiodic monolayer on the fivefold surface of icosahedral Al-Pd-Mn and that the quasiperiodicity propagates up to the second layer in sodium. Our photoelectron spectroscopy results show that the quasicrystalline alkali metal adlayer does not exhibit a pseudogap near the Fermi level, thought to be charactersitic for the electronic structure of quasicrystalline materials. Calculations based on density functional theory provide a model structure for the quasicrystalline alkali metal monolayer and confirm the absence of a pseudogap.