Band Structure and Properties of Cesium Metal

Abstract

Energy bands and wave functions for cesium metal have been obtained by an orthogonalized-plane-wave procedure using a conduction-electron potential constructed from first principles. The effects of correlation in the ground state have been included through a local model potential and are found to have a rather small influence on band properties. The Fermi surface is observed to be less distorted along the [110] direction than in earlier calculations, and is in better agreement with experiment. The ratios $\frac{k_F}{{k_F}^0}$ along three principal directions [110], [111], and [100] were found to be 1.032, 0.992, and 0.970, as compared to 1.033, 0.991, and 0.986 obtained from de Haas—van Alphen measurements. The calculated density of states is utilized to evaluate the specific heat, which, after suitable correction for electron-phonon interaction, is found to be about 1.03 times the experimental value. The spin susceptibility, after incorporating exchange enhancement effects, is predicted to be 0.7696×${10}^{-6\mathrm{}}$ ${\mathrm{cm}}^3$ volume units, in good agreement with a recent experimental value of 0.80×${10}^{-6\mathrm{}}$ inferred from the nuclear-magnetic-resonance measurements in liquid alkali-metal alloys. The Knight shift and the nuclear relaxation time $T_1$, which depend explicitly on the wave functions, are both found to be within 60% of experiment. Possible mechanisms which could improve the agreement of these two properties with experiment are discussed.