SYMMETRY BREAKING AND RESTORING UNDER HIGH PRESSURE: THE “SIMPLE” ALKALI METALS

Abstract

Light alkali metals such as lithium have been predicted to undergo a metal-insulator transition at high pressure, the insulating phase being characterized by a considerable reduction of lattice symmetry. Here, we argue that such a tendency towards symmetry reduction could be due to electron correlations. More specifically, we suggest that an ionic lattice surrounded by a Fermi liquid changes phase several times under pressure, oscillating between the symmetric phase and a low-symmetry dimerized phase, as a consequence of Friedet oscillations in the pair potential.

Keywords:

• Lithium
• Metal-insulator transition