[Perspective] Toward single-atom memory

Storing information in an ensemble of single-atom magnets represents the ultimate miniaturization of data storage technology, in which two specific orientations of each atomic magnetic moment represent a bit (a 0 or 1) of information (see the figure, panel A). The inherent dilemma in using a single-atom magnet is keeping it magnetized—or, in other words, being able to hold the information in one of the bit states without an external magnetic field for a useful amount of time and at practical t