Pressure-induced insulator-metal transition and collapse of magnetism in molecular solid oxygen

The electronic structure, the total energy and the charge and spin densities of molecular phases of solid oxygen are calculated by the first-principles full potential LMTO (FPLMTO) method. The following important results are obtained: (1) At ambient pressure the most stable state is the antiferromagnetic state. (2) Pressure-induced insulator-metal transition occurs by band overlapping which closes the indirect energy gap. At the transition volume, the magnetic moment still remains in each oxygen molecule. (3) With further decrease in the volume the magnetic moment disappears and the paramagnetic metallic phase is realized at the volumes corresponding to pressures higher than 100 GPa. (C) 2001 Elsevier Science Ltd. All rights reserved.