Two sheets of paper stacked together start to creep ever so slightly over each other when heated. That's roughly how layers of molybdenum disulfide, a material one atom thick, behave. At room temperature, they spontaneously slide at a speed of about one meter per second.

Previously, it was thought that shifting layers required overcoming a barrier, like dragging a heavy box over a threshold. But atomic-level calculations show there's almost no barrier. The motion doesn't happen as a shift of the whole sheet but as a wave of rearrangement at the boundaries between regions with different orientations. It's like a wrinkle moving across a carpet without the carpet itself shifting.

This behavior opens the way to memory devices where information is written by shifting layers with almost no energy cost.