Rui Zhou

Ordinary computer memory constantly uses energy to store ones and zeros. Superconductors, on the other hand, carry current with zero loss — if you could build memory from them, it would barely draw any power. The catch is that superconductors can't remember: their state changes too easily. Uranium ditelluride crystals turned out to be the exception.

Scientists peered into a two-dimensional magnet made of nickel atoms arranged in triangles using a method created by Isidor Isaac Rabi — nuclear magnetic resonance (similar to MRI). Inside, they found magnetic arrows that, in a strong field, froze into an 'up-up-down' pattern, like a formation of soldiers: two steps forward, one step back.

The surface of the uranium compound UTe2 crystal looks like a frozen sea: in some places, electrons move freely; in others, they get stuck near atoms. A scanning tunneling microscope, a device that probes the surface with an atomically sharp tip and senses individual electrons, revealed that this landscape is not random.