The chemistry of La on the Si(001) surface

TL;DR

This study uses advanced electronic structure calculations to explore how lanthanum (La) atoms adsorb and behave on the silicon (001) surface, revealing stable phases and oxidation state changes at different coverages.

Contribution

It provides the first detailed prediction of La chain formation, stable phases, and oxidation state transitions on Si(001) using state-of-the-art calculations.

Findings

La forms chains at low coverage

Stable phase at 1/5 monolayer coverage

Inert stable phase at 1/3 monolayer coverage

Abstract

This paper reports state-of-the-art electronic structure calculations of La adsorption on the Si(001) surface. We predict La chains in the low coverage limit, which condense in a stable phase at a coverage of 1/5 monolayer. At 1/3 monolayer we predict a chemically rather inert, stable phase. La changes its oxidation state from La(3+) at lower coverages to La(2+) at coverages beyond 1/3 monolayer. In the latter oxidation state, one electron resides in a state with a considerable contribution from La-d and f states.