Ordered oxide layers on the pentagonal surface of AlPdMn quasicrystal

Recently, we reported the structural investigation of the oxide layers grown on the pentagonal surface of icosahedral ${\text{Al}}_{70}{\text{Pd}}_{20}{\text{Mn}}_{10}$ quasicrystal based on low-energy electron diffraction. The oxide layer was described to consist of five twin domains rotated by $2\ensuremath{\pi}/5$ with respect to each other in accordance with the symmetry of the quasicrystalline substrate each of which having one twofold-symmetry direction of the substrate as a mirror plane. Here, we discuss the oxidation process in more detail and report the growth of different oxide structures depending on the sample temperature and its pretreatment. At room temperature, amorphous oxide layers form. In contrast five distinct and few-nanometer-large domains possessing an internal hexagonal structure with substantial amount of contribution from antiphase domain boundaries grow at 700\char21{}800 K for small and large coverage. In an intermediate range, a mixture of antiphase domain-boundary contributions and fractional-order spots characteristic to a $2\sqrt{3}(1\ifmmode\times\else\texttimes\fi{}1)R\ifmmode\pm\else\textpm\fi{}30\ifmmode^\circ\else\textdegree\fi{}$ reconstruction of the surface oxide layer is found which additionally stabilized the interface. The previously reported twin-domain model, which was derived after an ion bombardment of the preoxidized surface with subsequent reoxidation, is identified as an oxide layer grown on the (110) surface of a crystalline ${\text{Al}}_{50}{(\text{PdMn})}_{50}$ alloy as a result of the sputtering.