Premium
Frequency‐dependent exchange correction to the dielectric function of the electron gas (II)
Author(s) -
Brosens F.,
Devreese J. T.,
Lemmens L. F.
Publication year - 1977
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220800111
Subject(s) - dielectric function , dielectric , function (biology) , electron , condensed matter physics , chemistry , fermi gas , hartree , plasmon , logarithm , dielectric response , physics , atomic physics , quantum mechanics , mathematical analysis , mathematics , evolutionary biology , biology
The influence of the exchange interaction on the dielectric response of the homogeneous electron gas is investigated. Starting from an expression for the dielectric function obtained earlier, the function G ( q , ω) that describes the effect of exchange, is analysed. It is shown that G ( q ,ω) has a logarithmic singularity if ω = h ( qk F ± q 2 /2), which makes the full frequency dependence of this function very significant. The dielectric function with exchange differs from the Hartree approximation by a very peaked frequency dependent structure. It even has a pole of first order. Furthermore, due to exchange, the plasmon branch is substantially changed and does not penetrate in the pair creation region. Finally, the exchange interaction induces a zero in the dynamic structure factor, where in the Hartree approximation only a discontinuous derivative with respect to frequency occurs.