Analytical expressions for the local-field corrections in double-layer electron systems

We develop an extension of the sum-rule version of the Singwi, Tosi, Land, and Sjolander (STLS) scheme applied to a double-layer electron system. We present analytical expressions for the intralayer and interlayer static structure factors and corresponding local-field corrections which agree quite well with the full STLS calculations. Some applications of our basic results and further generalizations of our method are discussed.