Nanoscience under extreme forces

在原子水平上，物质可以通过施加大的力，特别是大的外部静电场来改变。在这样的磁场中，化学效应开始发挥作用，因为电子轨道被扭曲到如此程度，以至于原子或分子的化学特性发生了改变。通过这种方式，可以建立化学反应的新途径。技术相关性的例子是在原子探针断层扫描（APT）中使用的场离子显微镜中的场蒸发，以逐个原子和逐层绘制合金的组成。金属场蒸发的量子力学理论是在20世纪80年代末由我的小组和其他人发展起来的。近年来，利用ATP研究氧化物已成为人们关注的热点。然而，作为该领域的专家，Bernard Deconihout最近表示：“尽管APT已经在广泛的材料面板上提供了大量结果，但由于缺乏对半导体和氧化物中涉及的不同蒸发机制的理解，解释3D图像有时很困难。”我们将对绝缘体特别是氧化物的APT进行系统研究。正如我们最近在MgO上的试点项目所显示的那样，APT的好处将是巨大的。

At the atomic level matter can be modified by the application of large forces in particular by large external electrostatic fields. In such fields chemical effects come into play because the electronic orbitals get distorted to such a degree that the chemical characteristics of an atom or molecule become altered. In this way, new pathways in chemical reactions may be established. Examples of technological relevance are field evaporation in the field ion microscope that is used in Atom Probe Tomography (APT) to map the composition of an alloy atom by atom and layer by layer. The quantum mechanical theory of field evaporation of metals was developed in the late 1980s by my group and others. Recently it has become of interest to use ATP for the study of oxides. However, as an expert in the field, Bernard Deconihout, recently stated "Although APT has provided a large number of results on a wide panel of materials, interpretation of 3D images are sometimes difficult due to a lack in the understanding of the different evaporation mechanisms involved in semiconductors and oxides". We will make a systematic study of APT for insulators, in particular oxides. The benefits to APT will be substantial as our recent pilot project on MgO already showed.