Neutral Pair Wigner Crystal Formation in Semimetals

Abstract

The Wigner crystal formation of the neutral electron-hole pair in semimetals such as LaSb was studied by using a simplified phenomenological effective Hamiltonian model. It was shown that before the band gap closes, the transition to the Wigner crystal with a finite number of pairs occur but it resembles the Wigner crystal liquid. As the overlap between two bands increases, it changes to the usual band state with the Coulomb effect. Various puzzling properties in La-monopnictides as well as Ce-monopnictides can be explained by this model.