Experimental and Theoretical Study of Magnetic Breakdown in Magnesium

Abstract

It is found that the energy-band structure of magnesium in the symmetry plane $\ensuremath{\Gamma}\mathrm{KHA}$ of the Brillouin zone is such that regions of intersecting or nearly intersecting energy surfaces give rise to magnetic breakdown. A theoretical investigation of the profiles of the energy surfaces is carried out by means of an interpolation scheme based on values of the energy at the symmetry points taken from an existing orthogonalized-plane-wave (OPW) calculation. The energy gaps due to spin-orbit effects are computed using a three-OPW approximation.Experimental measurements of the de Haas-van Alphen effect for magnetic fields close to the $c$ axis are reported. A giant orbit of area larger than the cross section of the Brillouin zone is found. The experimental parameters for this orbit are in excellent agreement with the theoretical estimates.