Band narrowing and charge transfer in six intermetallic compounds

Self-consistent band calculations on six intermetallic compounds of the CsCl structure and on constituent bcc solids with the same lattice spacing show $3d$-band narrowing in the compounds and charge transfer between the compound constituents. The $d$-band narrowing in the compounds results from a lack of $d$ states on neighboring atoms into which electron tunneling can occur. In the case of compounds with two $d$-band constituents, we find an additional $d$-band narrowing due to mutual $d$-band repulsion. Charge transfers, found by a direct comparison of the charge densities in the compound and in the elemental solid, are always from the element with the higher Fermi energy to the element with the lower Fermi energy.