The Self-Consistent Band Calculation of Ca and Sr under High Pressure

Abstract

Electronic structures of Ca and Sr under high pressure are investigated by KKR method with four different types of the self-consistent potential: the Hartree-Fock-Slater, the approximate Averaged-Hartree-Fock and the other two potentials. In the HFS potential the relative position of the d -band is somewhat too low, so that it predicts the metal-semimetal transition at V / V 0 ≈0.84 for Ca, and Sr as semimetal already at normal pressure. On the other hand, the AHF potential predicts that the metal-semimetal transition occurs at V / V 0 ≈0.65 for Ca, and at V / V 0 ≈0.88 for Sr. The theoretical prediction is in good accord with experiments. At normal pressure, the Fermi energy is found to be just near the top of the density-of-states rather than at the valley of it, and the Fermi surfaces consist of a first zone monster and second zone caps, as was first proposed by Harrison.