FERMI-SURFACE OF TH WITHIN LOCAL-DENSITY FUNCTIONAL THEORY

The energy band structure, particularly the Fermi surface, is calculated for fee Th by a self-consistent, relativistic augmented-plane-wave method with the exchange and correlation potential in a local-density approximation. The extremal cross-sectional area of the Fermi surface is calculated carefully as a function of the direction of the normal on the {100} and {110} planes, which has been so far calculated only in three high-symmetry directions, and compared with the experimental results for the de Haas-van Alphen (dHvA) effect measured by Boyle and Gold (1969). As a result, it becomes possible to identify the origin of many dHvA frequency branches much more clearly. In addition, a new assignment of the theoretical and the experimental dHvA frequency branches is proposed, and the existence of several new dHvA frequency branches is predicted also.