Atomic Nanowires on the<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>Pt</mml:mi><mml:mo>/</mml:mo><mml:mi>Ge</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>001</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:math>Surface: Buried Pt-Ge Versus Top Pt-Pt Chains

Combining total-energy calculations, electronic-structure studies, and scanning tunneling microscopy (STM), we demonstrate that the observed one-dimensional nanowires are composed of Pt-induced Ge structures instead of Pt chains. Pt-Ge bonds are favored versus Pt-Pt ones. The novel tetramer-dimer-chain model explains STM features and the differential conductivity. The conduction path is related to the chain of alternating Pt-Ge atoms.