Fermi Surfaces of Cr, Mo, and W by the Augmented-Plane-Wave Method

The Fermi surfaces of chromium, molybdenum, and tungsten were calculated using linear-variation functions consisting of 19 augmented plane waves (APW). The muffin-tin potential was constructed from a superposition of atomic potentials centered on the lattice sites. The atomic orbitals were solutions of the Hartree-Fock-Slater self-consistent field. Constant-energy surfaces throughout the Brillouin zone and the volume contained by each of the regions were determined. The Fermi surface was selected from these energy surfaces by the requirement of equal hole and electron volumes. The density of states at the Fermi energy was determined from the slope of the volume-vs-energy curve. The Fermi surfaces of Mo and W were found to be almost identical and similar to the model postulated by Lomer for the Cr-group metals. The Fermi surface of Cr, however, differs from the other two by the disappearance of the hole pockets around $N$ and a shrinking of the knobs on the electron jack. A quantitative comparison between experimental results and the Fermi surface of Mo is presented.