CALCULATION OF THE SELF-ENERGY IN A LAYERED 2-DIMENSIONAL ELECTRON-GAS

The self-energy of a layered two-dimensional (2D) electron gas has bee n investigated using the Fermi-liquid approach. The zero- and finite-t emperature calculations including both single-particle and plasmon exc itations have been carried out. It is found that when the interlayer d istance is large compared to twice the effective Bohr radius a(B), the interlayer-coupling effects are small and the results correspond to t hose of a pure 2D electron gas. When the interlayer distance is smalle r than 2a(B), the results are similar to those of a three-dimensional (3D) system. At intermediate interlayer distances, the results show an interesting mixture of 2D and 3D behaviors. The linear temperature de pendence of the plasmon contribution to the quasiparticle damping at h igh temperatures in a layered 2D electron gas, obtained in this paper, may have some relevance to the explanation of the normal-state proper ties of the high-T, superconductors.