Breaking the pattern: structure and fundamental properties of bismuth and tellurium adlayers on platinum basal surfaces

• Both Bi and Te demonstrate a lot of similarities in their interaction with model platinum substrates. • At all coverages the adatoms are positively charged and interact repulsively with each other. • The adlayers’ stability depends on the balance between destabilizing effect of the Pt d-band centre shift and stabilizing depolarization of the adlayer. • Inclusion of spin–orbit coupling effects does not affect adsorption trends and work function in Bi(Te)/Pt systems. In this computational study the explicit interaction of Bi and Te with (111), (110), and (100) platinum surfaces was investigated, focusing on structural and electronic characteristics of the studied systems as a function of the adsorbate coverage. For Bi/Pt systems, good agreement was found between calculated results and previously published data. At all coverages adsorbed Bi or Te atoms interact repulsively. At coverages close to half a monolayer the structure of the adlayers on more open Pt(110) and (100) surfaces is defined by the geometry of the substrate, while on densely packed Pt(111) the regular pattern breaks and adsorbed Bi or Te layers become more disordered, as experimentally reported for Bi. Additionally, whereas the downshift on the d -band centre of Pt atoms in contact to the adatoms weakens the Pt-Bi(Te) bond, the depolarization of the adlayer contributes to the stabilization of the adatom-adatom interaction within the adlayer. Obtained results evidence that Bi and Te adlayers supported on Pt cannot be treated as a mere combination of their parts and, instead, must be considered as unique materials with properties different from their parent systems.