Prominent 5d-orbital contribution to the conduction electrons in gold

TL;DR

This study reveals that gold's conduction electrons are significantly influenced by 5d orbitals, unlike silver, where 4d electrons behave more like free electrons, highlighting fundamental differences in their electronic structures.

Contribution

The paper demonstrates the prominent 5d-orbital contribution to gold's conduction electrons using polarization-dependent hard x-ray photoemission, contrasting with silver's negligible 4d contribution.

Findings

Gold's conduction electrons have significant 5d-orbital character.

Silver's conduction electrons are more free-electron-like with minimal 4d contribution.

4d electron correlation effects are crucial for silver's conduction properties.

Abstract

We have examined the valence-band electronic structures of gold and silver in the same column in the periodic table with nominally filled d orbitals by means of a recently developed polarization-dependent hard x-ray photoemission. Contrary to a common expectation, it is found that the 5d-orbital electrons contribute prominently to the conduction electrons in gold while the conduction electrons in silver are to some extent free-electron-like with negligible 4d contribution, which could be related to a well-known fact that gold is more stable than silver in air. The 4d electron correlation effects are found to be essential for the conduction electron character in silver.