Growth and alloying of thin film Te on Cu(111)

We explore the growth and temperature-dependent alloying of Te on Cu(111) using a combination of low energy electron diffraction (LEED), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and scanning tunnelling microscopy (STM). Below 275 K, growth is rough and disordered. Above 275 K, there are two distinct surface phases: a surface substitutional alloy for coverages below 0.33 ML and a Cu3Te2-like alloy above 0.66 ML, with the phases coexisting at intermediate coverages. The alloy is consistent with the (111)-termination of an unusual phase with F 4 ¯ 3 m-symmetry that is well lattice-matched to the underlying Cu(111). It is relaxed and incommensurate, showing a long-range periodicity consistent with a floating overlayer.