The constant shrinking of memory in devices hits a wall: ultra-thin films usually lose their ability to hold a charge. Electric forces on the surface smear the data. Landau described this decay theoretically, and Coulomb’s law justified it.

But hafnium oxide breaks the rule. Computer simulations showed that the top atomic layer itself acts as a clever latch. When switching states, it instantly changes its electrical role — from attraction to repulsion and back. It all depends on what adjoins the surface — hydrogen or oxygen. This self-willed behavior of the atomic film is the secret of its memory.

Now engineers know: only films with a switchable surface layer will do. Even quantum effects at the boundary become interference. Algorithms from machine learning will search for such materials, and electron spectroscopy (essentially “X-raying” the structure) will verify them.