When an all-electron Wigner crystal (top) is squeezed too tightly, the electron wave functions begin to overlap (middle), and then create a quantum liquid (bottom).
The word "crystal" usually refers to atoms arranged in a lattice, but Wigner crystals are made entirely of electrons. A team of physicists have recently described how to make such a crystal by compressing an "electron liquid," and how to turn the crystal back into a liquid by squeezing some more. The team's computer models also indicate new and surprising behaviors of small electron crystals. The results suggest experiments that might allow simple and direct observation of Wigner crystallization.