Without a map, it can be just about impossible to know not just where you are, but where you’re going, and that’s especially true when it comes to materials properties. For decades, scientists have understood that while bulk materials behave in certain ways, those rules can break down for materials at the micro- and nano-scales, and often in surprising ways. One of those surprises was the finding that, for some materials, applying even modest strains — a concept known as elastic strain engineering — on materials can dramatically improve certain…