High-Pressure Structural Phase Transitions in Na, Mg, and Al

First-principles total-energy calculations by two independent methods predict new transition-metal-like sequences of stable crystal structures in the third-period simple metals Na, Mg, and Al, under increasing pressure. These structural phase transitions are controlled by $d$ electrons through the lowering and partial filling of the initially empty $3d$ band as the metals are compressed. A number of these transitions occur in the megabar range and below and could be investigated by existing experimental techniques.