Function follows form: When shape dictates functionality of quantum materials

From the sound of a violin to the waves in a pond, whenever physics is governed by wave equations the shape or boundary conditions of the wave are crucial in determining its spectrum. Even in quantum systems, when many electrons entangle into correlated manybody states, the emergent excitations still sense the shape of the crystal that confines them. Recent advances in Focused Ion Beam microfabrication have enabled breakthroughs in the shape control of 3D quantum systems, impacting and changing their symmetry and function by shape. For example, the triangular symmetry of atoms found in so-called Kagome superconductors can be frustrated in samples with cubic shape, leading to instabilities and switching behavior absent in the bulk – with potential utility in quantum technologies. I will review both the use of FIB in fabrication as well as the physics cases uncovered by this method at MPSD in Hamburg.