Augmented-Plane-Wave Calculations of the Electronic Structure of Intermetallic Compounds YCu and YZn

In order to understand the electronic structure of the rare-earth intermetallic compounds $\mathrm{RX}$, where $X=\mathrm{C}\mathrm{u},\mathrm{A}\mathrm{g},\mathrm{A}\mathrm{u}\mathrm{o}\mathrm{r}\mathrm{Z}\mathrm{n},\mathrm{C}\mathrm{d}\mathrm{a}\mathrm{n}\mathrm{d} R$ is a rare-earth element, the energy bands of the isomorphous compounds YCu and YZn have been calculated by the augmented-plane-wave method along different symmetry directions. The calculated Fermi energies for YCu and YZn are +0.42 and +0.47 Ry, respectively. The densities of states $N\left(E_F\right)$ at the Fermi level are obtained as 1.9±0.2 and 2.35±0.2 electrons/eV unit cell for YCu and YZn, respectively. This value for YCu is in good agreement with the experimental value of 1.32 electrons/eV unit cell obtained from specific-heat measurements. Also, the calculated change of density of states near the Fermi level is in the same direction as that obtained from specific-heat results on YCu substituted with small quantities of Ni or Zn. The implications of the calculated energy bands are discussed.