Temperature dependence of short-range correlations in the homogeneous electron gas

The temperature-dependent behavior of short-range correlations in a homogeneous three-dimensional electron gas at finite temperatures and finite degeneracies is presented. From the physical meaning of the pair distribution function for two electrons at the same location, one would expect a function which increases monotonically with the temperature. Instead, a decrease is found for small temperatures. This effect is investigated extensively within the framework of the random-phase approximation of static-local-field-corrected approaches. Moreover, by applying first-order perturbation theory the nonmonotonic behavior is proven to appear in the high-density limit also. Using a density-functional based model for short-range correlations, a physical interpretation is obtained. Finally, the results are discussed in a comprehensive way.