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，电子在围绕原子核的所谓轨道上运动。这些轨道和它们彼此之间的相互作用产生了许多材料性质，例如，机械稳定性和粘附性、光学、电学和磁性以及化学键合。因此，轨道对于从物理学到化学和材料科学到生物学的许多领域都至关重要。尽管他们的核心作用，它一直难以可视化和测量的固体内部的个别orbitals到目前为止，在这个项目中，我们将联合收割机的两种方法的透射电子显微镜和电子能量损失光谱仪，以表征个别原子内选定的样品。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米（约比光波长小一千倍），为了测量它们，电子束必须将非常特定的能量转移到样品上。因此，测量的信号非常弱且有噪声。为了克服这一挑战，将使用最新一代的仪器来达到理想的成像条件。此外，最佳的参数，如样品厚度，加速电压和能量转移将确定理论和实验。此外，我们将探讨新的成像技术，如波函数成形和微分相衬映射轨道的适用性，特别是界面和缺陷的轨道映射中发挥重要作用。一方面，关于轨道方向的一些结论仅由于样品在界面或缺陷附近的局部变化而成为可能。另一方面，它们对许多实际应用有着巨大的影响，如保护涂层的附着力、电子设备的效率或新催化剂的开发。因此，将在本项目中开发的轨道映射的新方法不仅将提高我们对轨道的理解，而且还将导致这种理解的更好的适用性。