Ground State of a Wigner Crystal in a Magnetic Field. II. Hexagonal Close-Packed Structure

Abstract

The energy of Wigner crystal of the hcp structure is calculated in magnetic fields. It is obtained as a sum of the static energy and the zero-point vibrational energy in the harmonic approximation. The zero-point energy of the hcp becomes lower than those of the bcc and fcc structures, which were previously obtained, above a critical strength of magnetic field. This leads to a structural phase transition from the bcc to the hcp as the magnetic field is increased. The crystal structure with the lowest energy is determined in the plane of density and field.