Structure of the (010) surface of the orthorhombic complex metallic alloyT-Al3(Mn,Pd)

Abstract

The atomic and electronic structures of the (010) surface of the $\mathrm{T}{\text{-Al}}_{3}$(Mn,Pd) complex metallic alloy is investigated by means of low-energy electron diffraction (LEED), scanning tunneling microscopy (STM), x-ray and ultraviolet photoelectron spectroscopy (XPS and UPS), x-ray photoelectron diffraction (XPD), and ab initio calculations. While structural imperfections are observed at the surface and out of the various possible terminations, the puckered P2 layer is identified as the only surface termination, thus pointing out the existence of a well-defined minimum in the surface energy landscape. The measured step heights correspond to distances between identical planes along the [010] direction in the bulk model, i.e., $b/2$. A bias dependency of the STM topography is found. The XPD and LEED patterns confirm the pseudotenfold symmetry of the sample. XPS and UPS show a more metallic signature of the $\mathrm{T}$ phase compared to Al-based quasicrystalline phases.