Abstract We report on first principles total energy calculations to describe the structural, electronic and magnetic properties of MnAl(0 0 1) surfaces. We have concentrated in structural models having 1 × 1 and 1 × 2 periodicities, since recent experiments of the similar MnGa(0 0 1) surface have found 1 × 1 and 1 × 2 reconstructions. Our calculations show the existence of two stable structures for different ranges of chemical potential. A 1 × 1 surface is stable for Al-rich conditions, whereas a Mn-induced 1 × 2 reconstruction appears after increasing the Mn chemical potential up to Mn-rich conditions. It is important to notice that experimentally, Mn rich conditions are important for improved magnetic properties. The Mn layers in both structures have ferromagnetic arrangements, but they are aligned antiferromagnetically with the almost no magnetic Al atoms. Moreover, the on top Mn atoms, which produce the 1 × 2 reconstruction, align antiferromagnetically with the second layer Mn atoms. These findings are similar to those obtained experimentally in MnGa thin films grown by molecular beam epitaxy. Therefore, this method could also be used to grow the proposed MnAl films.

中文翻译：

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Mn 在 τ-MnAl(001) 表面诱导 1×2 重建

摘要 我们报告了描述 MnAl(0 0 1) 表面的结构、电子和磁性能的第一原理总能量计算。我们专注于具有 1 × 1 和 1 × 2 周期性的结构模型，因为最近对类似 MnGa(0 0 1) 表面的实验发现了 1 × 1 和 1 × 2 重建。我们的计算表明，对于不同的化学势范围，存在两种稳定的结构。1 × 1 表面在富铝条件下是稳定的，而在将 Mn 化学势增加到富锰条件后，会出现 Mn 诱导的 1 × 2 重建。值得注意的是，在实验中，富含 Mn 的条件对于改善磁性能很重要。两种结构中的锰层都具有铁磁排列，但它们与几乎没有磁性的铝原子反铁磁排列。此外，产生 1 × 2 重构的顶部 Mn 原子与第二层 Mn 原子反铁磁排列。这些发现类似于在通过分子束外延生长的 MnGa 薄膜中实验获得的结果。因此，这种方法也可用于生长所提出的 MnAl 薄膜。