Observation of (6x2) and close-packed c(8x2) structures of dysprosium on W(100) - art. no. 033403

摘要

Low-energy electron diffraction (LEED) results have showed that Dy films grown on W(100) at room temperature are highly disordered. By growing Dy on W(100) at 470 K, an epitaxial relation was found for Dy/W(100) in which Dy(0001)parallel toW(100) and Dy[11 (2) over bar0]parallel toW[010]. Annealing to 770 K improved significantly the quality of the LEED pattern. The Dy hexagonal lattice is slightly distorted along the [010] and [001] axes of the W(100) substrate, resulting in a c(8x2) commensurate unit cell. The lattice constants of the Dy overlayer have been found to be extended by 0.7% (along W[010]) and by 1.5% relative to the Dy bulk lattice constant. Scanning tunneling microscopy (STM) studies of the annealed film showed that this annealing temperature for Dy/W(100) will produce flat and well-ordered films of c(8x2) structure. STM studies have shown that Dy also forms a (6x2) structure in some regions of the surface. [References: 9]