There is an urgent need to understand the relationship between oxide thin-film surface plane and its electronic properties because of its key role in molecular adsorption and surface reactivity as requested in optimal applications of magnetism to catalysis. The present work intends to resolve this open issue by investigating the surface structure and electronic properties of Mn₃O₄ thin films. To this end, well-defined Mn₃O₄ (110) and (001) surfaces were prepared and their electronic properties were explored by X-ray linear dichroism, XLD (the search light effect). The Mn₃O₄ thin films were extensively prepared on distinct noble metal substrates (Au(111), Cu (111), Ag (001)) with the aim of disentangling the film’s electronic structure and their corresponding film strain from their free surface, bulk, and interface contribution. Our experiments revealed the sensitivity of the 3d orbital occupancy and their intensity ratio (d${}_{x^2-y^2}$/d${}_{3z^2-r^2}$) to the surface orientation. The variation of relative 3d occupation as a function of strain was quantified by using the XLD sum rules. These results reveal important aspects for the identification and further engineering of well-defined crystallographic surfaces in several fields of applications.

迫切需要了解氧化物薄膜表面平面与其电子性质之间的关系，因为它在分子吸附和表面反应性中起关键作用，这是磁性在催化的最佳应用中所要求的。目前的工作旨在通过研究 Mn ₃ O ₄薄膜的表面结构和电子特性来解决这个悬而未决的问题。为此，制备了明确定义的 Mn ₃ O ₄ (110) 和 (001) 表面，并通过 X 射线线性二色性 XLD（探照光效应）探索了它们的电子特性。Mn ₃ O ₄在不同的贵金属基材（Au（111）、Cu（111）、Ag（001））上广泛制备薄膜，目的是从自由表面、体积和界面贡献中解开薄膜的电子结构和相应的薄膜应变. 我们的实验揭示了 3d 轨道占有率的敏感性及其强度比（d${}_{X^2-{是}^2}$/d${}_{3z^2-r^2}$) 到表面方向。相对 3d 占用的变化作为应变的函数通过使用 XLD 总和规则进行量化。这些结果揭示了在多个应用领域中识别和进一步设计明确定义的晶体表面的重要方面。