Evidence for a deconstructed “even” flat phase on the Pd(110) + K 1 × 2 surface

Abstract

The existence of a 1 × 2 missing row reconstruction on fcc metal (110) surfaces leads to a particularly rich variety of possible disordered phases. Five distinct disordering scenarios have been predicted for the 1 × 2 missing row reconstruction, differentiated by the relative energy cost to generate the different types of defects that can form on this surface. In this work we present high resolution LEED data for the alkali coverage driven 1 × 2 → 1 × 1 transition on Pd (110) + K. Superlattice and integer diffraction peaks as a function of potassium coverage have been analyzed. The width and shift of the superlattice diffraction peaks are found to be consistent with a transition to the deconstructed “even” phase. This transition is driven by the formation of bound steps. No evidence of isolated step formation is found in the coverage range 0 < θ < 0.4.