TaC(110): a periodic facet reconstruction studied by LEED and STM

A simple model is established to describe diffraction phenomena (LEED) from a unidirectionally reconstructed TaC(110) surface. By comparing diffraction data with results of detailed simulations, the reconstruction is found to consist of alternate (100) and (010) facets propagating periodically along the [110] direction like an irregular ridge-and-valley grating, with (110) terraces completely absent. The irregularity is due to variation in facet sizes, and the mean separation is determined to be L = 6 lattice spacings. The validity of this model is supported by STM imaging results which confirm the structure obtained from the LEED-data analysis.