Silicon devices can be squeezed only so small, but scientists, eager to keep Moore’s Law on track, are always searching for alternatives that may squeeze them smaller still. One of the most fascinating is a class of crystals known as perovskites, named after a 19th-century Russian mineralogist.
Perovskites form three-dimensional atomic arrays made of alkaline metals, like magnesium and strontium; transition metals, like titanium and chromium; and oxygen. They somewhat resemble their more famous copper-based cousins, the high-temperature superconducting ceramics, whose discovery won Nobel Prizes in physics for IBM’s J. Georg Bednorz and K. Alexander Muller. By switching around the distribution of their elements, researchers can tailor perovskites to be insulators, magnetic materials, semiconductors or superconductors — “the chameleons of physics,” as Bednorz calls them.