Wednesday, February 8, 2017
Much of our modern science and technology relies on functional materials, and their properties can be related to defects and disorder at the atomic scale. Traditional crystallography, which is reliant on periodicity, cannot study such structures. My work goes beyond crystallography, by combining advanced electron microscopes with powerful tomographic reconstruction algorithms. Atomic electron tomography (AET) is now able to precisely localize the 3D coordinates of individual atoms in materials without any prior assumption of underlying structure. It reveals a variety of complex atomic structures; including grain boundaries, chemical order/disorder, phase boundaries, and anti-site point defects. Combined with quantum mechanical calculations, AET provides an atomic-level understanding of material properties such as 3D strain tensors, magnetic moments and local magnetocrystalline anisotropy. Understanding the relationship between atomic structure and material properties will open up new avenues in condensed matter physics as well as allow the rational design of novel materials at the atomic scale.