Advanced Transmission Electron Microscopy

The primary goal of my research is to enable an atomic-scale understanding of energy-relevant materials by advanced transmission electron microscopy. We combine quantitative atomic resolution imaging, spectroscopy and in situ microscopy techniques to probe and observe materials under realistic conditions. Ultimately, we want to establish new microscopy methods to image the dynamic evolution of materials at three-dimensional atomic resolution. The four main pillars of our research are:

1. Quantitative atomic resolution imaging: We develop methods in the scanning transmission electron microscope to obtain quantitative information of complex materials and interfaces at atomic resolution. We apply the techniques to image novel interfacial structures, ferroic oxides and complex quantum materials.

2. Multimodal electron microscopy: Four-dimensional scanning electron microscopy is used to determine local magnetic and electric fields, and to resolve light elements at atomic resolution. We develop electron ptychography techniques to image complex materials and interfaces towards obtaining three-dimensional atomic resolution. Spectroscopic techniques are used to determine the local composition, electronic structure and bonding down to the atomic level.

3. In situ electron microscopy: We design new experimental setups to observe dynamic material evolution under external stimuli. The in situ microscopy techniques range from high temperature to cryogenic conditions while applying electrical bias, magnetic fields or strain to the samples. These methodologies are combined with novel imaging modalities to probe the evolution of atomic structure, composition and magnetic texture.

4. Computational microscopy: We use computational tools to analyze and simulate the multidimensional datasets to turn the data into physics-based quantities. Image simulations provide a direct link to atomic structures obtained from first-principles and atomistic simulations. Machine learning models are developed to automatically quantify the microscopy data and to pave the way for autonomous microscopy operation.

We combine atomic imaging, dynamic probing of materials under external stimuli and novel computational methods to establish a holistic understanding of material functionality down to the atomic-scale.