Imaging three phases of iodine on Ag (111) using low-temperature scanning tunneling microscopy

We investigated the adsorption of iodine on Ag (111) in ultra-high vacuum. Using low-temperature scanning tunneling microscopy (LT-STM) measurements we catalog the complex surface structures on the local scale. We identified three distinct phases at various iodine coverage which we tentatively associate with three phases previously reported in LEED experiments ((root 3X root 3) R30 degrees, triangular, hexagonal). We used Fourier-space and real-space analysis to fully characterize each phase. While Fourier analysis most easily connects our measure-ments to previous LEED studies, the real-space inspection reveals local variations in the superstructures of the hexagonal and triangular phase. The latter, observed here for the first time by LT-STM, appears to be stabilized by one or two adatoms sitting at the center of a rosette-like iodine reconstruction. The most stunning discovery is that variation in the adatom separation of the triangular phase reflects the Ag (111) surface lattice.

Automated summary

We investigated the adsorption of iodine on Ag (111) surface in ultra-high vacuum using low-temperature scanning tunneling microscopy (LT-STM). We identified three distinct phases and characterized each phase using Fourier-space and real-space analysis. The most significant finding is that the adatom separation in the triangular phase reflects the surface lattice of Ag (111).