Heat and electricity usually go hand in hand, but making heat turn into current is no easy task. The material GdTe3, a layered crystal with a metallic sheen, when cooled to 20 kelvins (that's −253 °C) and placed in a strong 13.5-tesla magnetic field, showed something unexpected: its ability to generate electricity from heat shot up by 1075%.
The secret lies in so-called Weyl points — special points in the electronic structure where electrons behave as if they have no mass. The magnetic field rearranges the crystal's electronic levels, and these points start actively participating in heat and charge transport. As a result, the thermoelectric efficiency of the material breaks records among metals.
The practical benefit is obvious: solid-state coolers made from such materials could work without compressors or refrigerants, simply by using an electric current. And in the future, they might also more efficiently harvest waste heat in industry.
Gadolinium telluride GdTe3 is a layered material; its crystals resemble a stack of paper, where each sheet conducts electricity in its own way.
In Arthur C. Clarke's novel "The City and the Stars," crystals that convert heat into light are mentioned — surely a distant relative of GdTe3?