Orbital Mapping Near Interfaces

界面附近的轨道测绘

• 批准号: 423465915
• 负责人: Professorin Dr. Ute Kaiser
• 金额: --
• 依托单位: Zentrale Einrichtung Elektronenmikroskopie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/423465915?language=en
• 关键词: Orbital; Mapping; Near; Interfaces

According to quantum mechanics, electrons move in so-called orbitals around the atomic nuclei. These orbitals and their interaction with one another give rise to numerous materials properties like, e.g., mechanical stability and adhesion, optical, electrical, and magnetic properties as well as chemical bonding. Therefore, orbitals are of paramount importance for many fields from physics over chemistry and materials science to biology. Despite their central role, it has been difficult to visualize and measure individual orbitals inside of solids so far.In this project, we will combine the two methods of transmission electron microscopy and electron energy loss spectrometry to characterize individual atoms inside selected samples. To that end, the size of the orbitals as well as the required measurement precision pose a significant challenge: they are less than one billionth of a meter in size (about a thousand times smaller than the wavelength of light) and for measuring them, the electron beam has to transfer a very specific amount of energy to the sample. Hence, the measured signal is very weak and noisy. To overcome this challenge, latest-generation instruments will be used to reach ideal imaging conditions. In addition, optimal parameters such as sample thickness, acceleration voltage and energy transfer will be determined both theoretically and experimentally. Moreover, we will investigate the suitability of novel imaging techniques such as wavefunction shaping and differential phase contrast for mapping orbitals.Especially interfaces and defects play an important role for orbital mapping. On the one hand, some conclusions about the direction of orbitals only become possible due to the local changes of the sample in the vicinity of interfaces or defects. On the other hand, they have a huge impact on many practical applications such as the adhesion of protective coatings, the efficiency of electronic devices, or the development of new catalysts. Thus, the novel approaches to orbital mapping that will be developed in this project will not only improve our understanding of orbitals but will also lead to a better applicability of this understanding.

根据量子力学，电子在原子核周围的所谓轨道中移动。这些轨道及其彼此相互作用产生了许多材料特性，例如机械稳定性和粘附，光学，电气和磁性特性以及化学键合。因此，轨道对从化学和材料科学到生物学的许多领域至关重要。尽管它们的中心作用，但到目前为止，很难可视化和测量固体内部的单个轨道。在这个项目中，我们将结合两种透射电子显微镜和电子能量损耗光谱法，以表征所选样品中的单个原子。为此，轨道的大小以及所需的测量精度构成了一个重大挑战：它们的大小不到十亿分之一（比光的波长小约一千倍），并且为了测量它们，电子束必须将非常特定的能量传递给样品。因此，测得的信号非常弱且嘈杂。为了克服这一挑战，最新一代工具将用于达到理想的成像条件。此外，将在理论上和实验上确定最佳参数，例如样品厚度，加速度电压和能量传递。此外，我们将研究新型成像技术的适用性，例如波函数形状和绘图轨道的差异相对比。尤其是接口和缺陷对于轨道映射起重要作用。一方面，关于轨道方向的一些结论仅是由于样本在接口或缺陷附近的局部变化而成为可能的。另一方面，它们对许多实际应用产生了巨大影响，例如保护性涂料的粘附，电子设备的效率或新催化剂的发展。因此，在该项目中将开发的轨道映射的新颖方法不仅会改善我们对轨道的理解，而且还将带来这种理解的更好适用性。