Protection of one-dimensional Si chains embedded in Pt(111) and protected by a hexagonal boron-nitride monolayer

Abstract

Using scanning tunneling microscopy, we study the regime of submonolayer Si deposition on Pt(111) at 300 K. We find a novel network of one-dimensional chains embedded into the Pt surface. Even in ultrahigh vacuum, these chains disappear within a few hours in favor of clusters on top of the Pt surface. Exposing the chains to different gases reveals that CO effectively induces the lifting. However, the Si chains can be protected by a monolayer of hexagonal BN (h-BN) deposited prior to the Si deposition. Then, the chains survive even an exposure for ten min to air. Interestingly, the Si chains below the h-BN are rotated by 30∘ with respect to the ones on the bare Pt(111). This might be related to the anisotropic elastic modulus of the h-BN on top.