Two sets of swings, rocking in opposite directions, don’t tilt the platform. Yet their motion creates invisible vortices that push a ball sideways. Alternagnets behave just like that: the atomic magnetic arrows are perfectly balanced, but a hidden symmetry bends the heat flow.

Previously, a similar effect, called the anomalous Hall effect, was observed only for electric current in ferromagnets. Now, in crystals of MnTe and CrSb, its thermal analogue has been discovered: atomic vibrations (phonons) are deflected sideways without an external magnet. This entropic thermal Hall effect turned out to be an intrinsic property of alternagnets, directly tied to their internal magnetic pattern.

The discovery expands the standard model of magnetism and promises intriguing applications. If you stack layers of this material in the right order, heat will naturally veer sideways, acting as a contactless refrigerator. And in the future — memory that is read not by current but by a thermal pulse.