Enhancement of the density of states at the Fermi level due to oxygen atoms in noble metals

TL;DR

This paper demonstrates that disordered oxygen atoms in noble metals significantly increase the density of states at the Fermi level, potentially leading to novel phenomena in nano-structured materials.

Contribution

It reveals the effect of disordered oxygen atoms on the DOS at the Fermi level in noble metals, highlighting a new way to modify electronic properties.

Findings

Oxygen induces a peak in DOS at $E_F$ in noble metals.

Disordered oxygen broadens flat bands related to O 2$p$ orbitals.

Potential for novel phenomena in oxygen-rich noble metal nanostructures.

Abstract

The interaction of oxygen with noble metals such as silver has been an important topic of research for many decades. Here, we show occurrence of a peak in the density of states (DOS) at the Fermi level ($E_F$) when oxygen atoms occupy disordered substitutional positions in noble metals such as Ag, Au or Ag-Au alloy. This results in large enhancement of DOS at $E_F$ with respect to Ag or Au metal. Its origin is attributed to O 2$p$ related disorder broadened flat band that straddles almost all the high symmetry directions of the Brillouin zone. Our work suggests that if a large concentration of disordered oxygen can be realized in nano-structures of noble metals, it may lead to interesting phenomenon.