BAND STRUCTURE AND PROPERTIES OF CESIUM METAL

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 kFkF0 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 cm3 volume units, in good agreement with a recent experimental value of 0.80×10-6 inferred from the nuclear-magnetic-resonance measurements in liquid alkali-metal alloys. The Knight shift and the nuclear relaxation time T1, 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. © 1969 The American Physical Society.