High-coverage surface phases of tellurium on Ni(111)

Abstract

The complex surface phases formed when tellurium is adsorbed to high coverage (>0.4 monolayer) on Ni(111) have been studied using a mirror electron microscope–low-energy electron diffraction apparatus and Auger electron spectroscopy. The unit meshes of the complex overlayer structures all have one side along the [1,−1] surface direction with length equal to the Te–Te nearest-neighbor spacing in the (√3×√3)R30 structure and one side along the [11] direction with lengths of 10, 11, 13, 14, and 16 Ni–Ni nearest-neighbor spacings. These one-dimensional coincidence meshes can be described in terms of ordered dislocation structures in a compressed hexagonal Te unit mesh. Two intermediate phases with unequal diffraction beam spacings are also observed and transform with a small hysteresis into phases with equal spot spacings.