Equipment: MRI Consortium Track 2: Acquisition of an Aberration-Corrected Scanning Transmission Electron Microscope for Multidisciplinary Research and Training

The Major Research Instrumentation award is made to the University of Oregon to acquire a cold-field emission, aberration probe-corrected scanning transmission electron microscope (STEM) - the first of its kind at a university in the state of Oregon. This instrument advances materials research, enables next-generation electron optics, and provides training for graduate and undergraduate students. By integrating the electron microscope into the Center for Advanced Materials Characterization at Oregon, a comprehensive research core facility with open access and highly qualified staff, the microscope is accessible to academic and industry users across the Pacific Northwest, accelerating research across materials science, electron optics, quantum information sciences, and microelectronics. An aberration-corrected scanning transmission electron microscope is an essential and versatile analytical tool for characterizing atomic structures and properties of matter at the highest spatial resolution. Specifically, a STEM with a spherical aberration corrector for the probe is required for research efforts in materials science and quantum physics conducted at the University of Oregon, Oregon State University and nearby institutions. This includes investigations into new physical phenomena that hinge upon measurements of atomic positions such as the relationship between structural chirality and charge density in Weyl-semimetals with novel topological magneto-electric responses or emergent behaviors at the atomic interface of magnetic topological skyrmions and superconductors, which differs greatly from its bulk constituents. The atomic-layered van der Waals heterostructures can be engineered in three-dimensions to encompass thermoelectric, photoelectric, or magnetic properties that depend sensitively upon the atomic nanoarchitecture. Here, the layer thicknesses and layer sequence can modify the amount of charge transfer between constituent layers leading to interfacial charge density and an alteration of the size and orientation of the polycrystalline domains. STEM imaging of these complex materials is critical for understanding how interfaces affect the function of these heterostructures. Only careful atom-by-atom characterization can provide suitable information about the underlying electronic properties of these systems. This tool also serves as a platform for developing new electron optics and imaging techniques such as STEM holography and interaction-free imaging that goes beyond conventional STEM imaging techniques. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.