Localized or propagating Majorana boundary modes are the key feature of topological superconductors. While being a rarity in natural compounds, the tailored manipulation of quantum matter offers novel opportunities for their realization. Specifically, lattices of Shiba bound states that arise when magnetic adatoms are placed on the surface of a conventional superconductor can be used to create topological minibands within the superconducting gap of the substrate. I will report how one can exploit the possibilities of scanning tunneling microscopy to create and probe adatom lattices with single atom precision to create topological crystalline superconductors. Their topological character and boundary modes are protected by the spatial symmetries of the adatom lattice. By combining scanning probe spectroscopy, spin-sensitive measurements, first principle calculations, and theoretical modeling we demonstrate the realization of two types of mirror- symmetry protected topological superconductors: (i) with full bulk gap and topological flatband edge states as well as higher-order corner modes and (ii) with symmetry-protected bulk nodal points. Our results show the immense versatility of Shiba lattices to design the topology and sample geometry of 2D superconductors.
