The formation of an ultra-thin aluminum oxide film at the Fe${}_{0.85}$Al${}_{0.15}$(110) surface (A${}_2$ random alloy) has been studied by a variety of surface sensitive techniques (X-ray photoemission, low-energy electron diffraction, surface X-ray diffraction and scanning tunneling microscopy) supplemented by {} atomistic simulations. Since iron is not oxidized in the conditions used, the study focused on the coupling between aluminum oxidation and segregation processes. Compared to the bare surface, whose average composition (Fe${}_{0.6}$Al${}_{0.4}$) is closer to the B${}_2$-CsCl structure over a $\sim 3$~nm depth, the oxidation hardly affects the subsurface segregation of aluminum. All the structural and chemical fingerprints point to an oxide film similar to that found on NiAl(110). It is a bilayer ($\sim 7.5$~thick) with a composition close to Al${}_{10}$O${}_{13}$ and a large $(18.8\times 10.7)$~${}^2$ nearly rectangular unit cell; an almost perfect match between substrate periodicity and the $(1\times 2)$ oxide supercell is found. Nevertheless, microscopy reveals the presence of anti-phase domain boundaries. Measured Al 2p and O 1s core level shifts match calculated ones; their origin and the relative contributions of initial/final state effects are discussed. The ubiquity of the present oxide on different supports asks for the origin of its stability.

中文翻译：

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富Al的Fe0.85Al0.15（110）表面的氧化物

在铁上形成超薄氧化铝膜${}_{0.85}$铝${}_{0.15}$（110）表面（A${}_2$已通过{}原子模拟补充的各种表面敏感技术（X射线光发射，低能电子衍射，表面X射线衍射和扫描隧道显微镜）研究了无规合金）。由于铁在使用的条件下不会被氧化，因此研究集中在铝氧化与偏析过程之间的耦合上。与裸露表面相比，其平均成分（铁${}_{0.6}$铝${}_{0.4}$）靠近B${}_2$-CsCl结构 $〜3$在约1nm的深度，氧化几乎不会影响铝的表面偏析。所有的结构和化学指纹均指向类似于NiAl（110）上发现的氧化膜。它是双层的（$〜7.5$〜厚）的成分接近Al${}_{10}$Ø${}_{13}$ 和一个大 $（18.8\times 10.7）$〜${}^2$近乎矩形的晶胞；底物周期与$（\mathrm{1个}\times 2）$发现氧化物超级电池。尽管如此，显微镜显示出反相畴界的存在。测得的Al 2p和O 1s核心能级位移与计算得出的相符；讨论了它们的起源以及初始/最终状态效应的相对贡献。本氧化物在不同载体上的普遍性要求其稳定性的来源。