Thomas Brumme

Shine light on an FePS3 crystal, and it responds with its own glow, like a neon sign, but much fainter and in the infrared range. This glow is not random: it depends on how the crystal is oriented. The scientists took samples from a thick chunk down to a single-atom layer and observed four emission bands — at 1.24 electronvolts, 1.79, 2.3, and 2.56.

Honeycombs are built from identical cells, but tweak the shape of just one, and the whole structure gains new properties. Researchers did something similar to create a magnet without a single metal atom. They took flat carbon molecules shaped like triangles, triangulenes, and arranged them in a hexagonal lattice, just as bees build honeycombs.