  Phase change memory has been developed into a mature technology capable of
storing information in a fast and non-volatile way, with potential for
neuromorphic computing applications. However, its future impact in electronics
depends crucially on how the materials at the core of this technology adapt to
the requirements arising from continued scaling towards higher device
densities. A common strategy to finetune the properties of phase change memory
materials, reaching reasonable thermal stability in optical data storage,
relies on mixing precise amounts of different dopants, resulting often in
quaternary or even more complicated compounds. Here we show how the simplest
material imaginable, a single element (in this case, antimony), can become a
valid alternative when confined in extremely small volumes. This compositional
simplification eliminates problems related to unwanted deviations from the
optimized stoichiometry in the switching volume, which become increasingly
pressing when devices are aggressively miniaturized. Removing compositional
optimization issues may allow one to capitalize on nanosize effects in
information storage.
