A Dutch group has managed to demonstrate a new storage device which is able to use single atoms to store information . It has chlorine atoms on a copper substrate (note, these are nice common substances, no rare earths etc.), it stores data using the position of a chlorine atom. The surrounding chlorine atoms tend to stabilize the position. The only downsides are that it requires a scanning tunneling electron microscope, a temperature of 77 Kelvin, and it takes half an hour to write 1K of data. However, as a proof of concept it's great as it can store two to three orders of magnitude more data per unit area than conventional storage media (hard drives and SSD). Here are links to a BBC write up and the Nature Nanotechnology article.