New aspects on the Ir(110) reconstruction: Surface stabilization on mesoscopic scale via (331) facets

Abstract
Scanning tunneling microscopy and low-energy electron diffraction of clean Ir(110) reveal a surprising novel route for the (110) surface of a fcc metal to stabilize its surface configuration: The Ir(110) surface is characterized by mesoscopic grooves of several 100 nm length along the direction of the close-packed rows and depths between 0.5 and 1.5 nm. Extended (331) facets on the walls and local unreconstructed (110) structures on the ridges are observed. Ir(110) obviously strongly differs from Au(110) and Pt(110), which exhibit (1×2) missing-row-type reconstructions with (111) microfacets.