A Local-Density Band Theory for the Fermi Surface of the Heavy-Electron Compound CeRu₂Si₂

Abstract

On the basis of the itinerant-electron model for the 4f electrons, the energy band structure and the Fermi surface are calculated for the metamagnetic heavy-electron compound CeRu 2 Si 2 having the low-temperature electronic specific heat coefficient γ of 350 mJ/K 2 mol. by a self-consistent symmetrized relativistic APW method with the exchange and correlation potential in a local-density approximation. The main Fermi surface consists of a large closed hole sheet and a complicated electron sheet like a jungle gym. The Fermi surface topology is consistent with the experimental result for the high-field magneto-resistance. By comparison with the electronic structure of LaRu 2 Si 2 , effects of the 4f bands on the Bloch states on the Fermi surface in CeRu 2 Si 2 are investigated in detail. Strong evidences for existence of the electron sheet are found in available experimental de Haas-van Alphen frequencies. The enhancement factor for γ is estimated as 38.