Fe Nanoclusters on the Ge（001） Surface Studied by Scanning Tunneling Microscopy, Density Functional Theory Calculations and X-Ray Magnetic Circular Dichroism

Ge (001 ) 表面上的 Fe nanoclusters 的生长用低温度的扫描通道显微镜学(STM ) 和密度被学习了功能的理论(DFT ) 计算。STM 结果显示 Fe 在 Ge (001 ) 表面上起核心作用，形成一致尺寸的秩序井然的 nanoclusters。取决于准备条件， nanoclusters 的二种类型被观察在 nanocluster 以内有四或十六个 Fe 原子。结果被 DFT 计算证实。退火在 420 K 的 nanoclusters 导致 nanorow 结构的形成，由于在如此的温度的簇活动性。在 Ge (001 ) 表面上形成的 Fe nanoclusters 和 nanorow 结构显示出由 X 光检查磁性的圆形的二色性测量了的 superparamagnetic 行为。

The growth of Fe nanoclusters oN the Ge（001） surface has been studied using low-temperature scanning tunneling microscopy （STM） and density functional theory （DFT） calculations. STM results indicate that Fe nucleates on the Ge（001） surface, forming well-ordered nanoclusters of uniform size. Depending on the preparation conditions, two types of nanoclusters were observed having either four or sixteen Fe atoms within a nanocluster. The results were confirmed by DFT calculations. Annealing the nanoclusters at 420 K leads to the formation of nanorow structures, due to cluster mobility at such temperature. The Fe nanoclusters and nanorow structures formed on the Ge（001） surface show a superparamagnetic behaviour as measured by X-ray magnetic circular dichroism.