ELECTRONIC-STRUCTURES OF NEWLY PREDICTED INTERCALATION COMPOUNDS LITHIUM INTERCALATED ALPHA-BORON

New types of intercalation compounds by intercalating lithium atoms in to semiconducting alpha-rhombohedral boron are predicted theoretically , based on the ab initio total-energy pseudopotential calculations in the local density approximation. A novel interesting feature of these new materials is to exhibit a possibility that both donor- and accepto r-type metallic compounds are obtained from the same species of interc alant atom, depending on the positions of an intercalant. It is shown by the total energy calculations that donor-type compound in which Li are intercalated into the center of a rhombohedral unit cell is the mo st stable.