Dielectric response functions and Coulomb repulsion parameters in bcc and 9R lithium

Abstract

The static dielectric response functions are calculated for both the room-temperature bcc and low temperature 9R phases of Li, and used for estimating the Coulomb repulsion parameters (mu*). With a full dielectric matrix approach within the local-density-functional approximation, the values of mu* for bce and 9R Li are estimated to be 0.157 and 0.160, respectively, much higher than most estimates for sp metals. The enhancement of mu* is attributed to the weak dielectric screening caused by the exchange-correlation effect and the peculiar conduction-band structure with a large dip in the density of states.