Light hits a thin film, and an electric current instantly appears in it. This is how a pair of two materials works: molybdenum disulfide and cobalt. The first is a semiconductor, the second is a magnet. Between them, as it turns out, an invisible intermediary layer is born.
Scientists shone a laser on the film at different wavelengths. It turned out that the current strength changes, but the speed of its appearance does not. The secret lies in the interlayer: it absorbs light differently depending on its color. Then the energy is transferred to cobalt, which produces the current. The interlayer acts as a translator between light and magnet.
Such films could become the basis for ultrafast sensors and data processing devices. Instead of electrical signals, light; instead of slow switching, instantaneous response.
Molybdenum disulfide resembles graphite: it can be exfoliated into sheets one atom thick. But unlike graphite, it is a semiconductor, so it is used in flexible electronics.
In Stanislaw Lem's novel "Solaris," the planet's ocean reacts to radiation by changing its structure. Here, the interlayer also "responds" to light, but strictly according to the laws of physics.