Formation of the Pd atomic chain in hydrogen atmosphere

TL;DR

This study demonstrates that hydrogen atmosphere enables the formation of stable palladium atomic chains, with distinct configurations and conductance properties, through combined experimental and theoretical analysis.

Contribution

It reveals hydrogen's role in facilitating Pd atomic chain formation and identifies two atomic configurations with different conductance behaviors.

Findings

Atomic chains formed only in Pd with hydrogen, not in clean 3d/4d metals.

Two configurations: short hydrogen-adsorbed and long hydrogen-incorporated chains.

Distinct conductance levels observed for the two chain types.

Abstract

The formation of a Pd atomic chain in a hydrogen atmosphere was investigated by measurements of conductance and vibrational spectroscopy of a single molecular junction, and the theoretical calculation. While atomic chains were not formed for clean 3d and 4d metals, in the case of Pd (a 4d metal) atomic chains could be formed in the presence of hydrogen. Stable atomic chains with two different atomic configurations were formed when the Pd atomic contact was stretched in a H$_{2}$ atmosphere; highly conductive short hydrogen adsorbed atomic chain and low conductive long hydrogen incorporated atomic chain.