Quantum Vortex of Electron-Hole Pairs: From Excitons to Topological Conductors
In two-dimensional crystals, electrons and holes, quasiparticles corresponding to the absence of an electron and carrying positive charge, attract each other, forming bound pairs called excitons. When cooled strongly, as thermal fluctuations die down, the motions of many excitons can synchronize, like a coordinated dance.