  Advances in scaling down heterostructures and having an improved interface
quality together with atomically-thin two-dimensional materials suggest a novel
approach to systematically design materials. A given material can be
transformed through proximity effects whereby it acquires properties of its
neighbors, for example, becoming superconducting, magnetic, topologically
nontrivial, or with an enhanced spin-orbit coupling. Such proximity effects not
only complement the conventional methods of designing materials by doping or
functionalization, but can also overcome their various limitations. In
proximitized materials it is possible to realize properties that are not
present in any constituent region of the considered heterostructure. While the
focus is on magnetic and spin-orbit proximity effects with their applications
in spintronics, the outlined principles provide also a broader framework for
employing other proximity effects to tailor materials and realize novel
phenomena.
