Melting criteria for classical and quantal Wigner crystals

Liquid structure and potential energy considerations lead to an approximate correspondence between the strongly coupled quantal electron plasma near the Wigner transition and its classical counterpart. However no such correspondence exists between the coupling strengths for the two freezing transitions. Electron tunnelling must therefore be important in determining the quantal Wigner transition, a possible quantal picture being proposed by analogy with Zener's idea of classical 'ring' diffusion. (author)