Long-distance relationships of particles: Electron-hole pairs in two-dimensional crystals

When light of specific frequency hits a semiconductor crystal, it is absorbed and produces a excitation, a state of higher energy. In solar cells, this energy can be converted into electricity and used. In two-dimensional crystals, which consist of only a few atomic layers, so called "excitons" are the protagonists of these processes: These excitations from light incidence consist of one particle of positive charge and one of negative charge. Yet, two-dimensional crystals host a sheer zoo of excitons, making it hard to tell the kind of excitons dealt with in specific situations. Researchers of TU Dresden, in collaboration with an international team, now identified the nature of interlayer excitons in two-dimensional crystals. Their findings were published in the journal Nature Physics.