Yang-hao Chan

A single-atom-thick sheet of tungsten telluride is like thin foil: electrons can't pass through because there's a band gap between their possible states, like a moat you can't jump across. Add two more layers, and the moat disappears; the material becomes a metal, and current flows. Add more layers, and the properties change again, as if someone is flipping modes with a single button.

Lossless current is the dream of energy technology. Some materials become superconductors, but usually only at extreme cold. Recently, in the family of nickelates, compounds based on nickel, candidates were found that work at higher temperatures.