Si(1Â 1Â 1) surface functionalized with H-bonded SAM: A theoretical study

► The Si(1 1 1) surface fuctionalized with a H-bond SAM based on propyl-urea molecules is investigated. ► Optimal coverage corresponds to 1/2 ML for maximizing H-bond formation. ► The monomer gives raise to a different surface periodicity. ► Occurrence of the most stable structure is experimentally revealed by a decrease of the Si(1 1 1) ionization potential and the change in periodicity from the STM surface image.