EFFECT OF MANY-BODY CORRECTIONS ON INTERSUBBAND OPTICAL-TRANSITIONS IN GAAS-ALXGA1-XAS MULTIPLE QUANTUM-WELLS

A self-consistent calculation of the energy levels of n-doped quantum wells (MQW) is reported. The eigenstates of the system are calculated from a four-bank k.p. Hamiltonian. The Hartree and exchange-correlation components of the Coulomb interaction are included self-consistently. The Hartree component is included by solving the Poisson equation; the exchange-correlation interaction is incorporated within the density-functional scheme. Also included are the vertex and depolarization effects which modify the intersubband transition energies. All of these many-body corrections are shown to strongly influence the ground to excited state transition within the conduction band. Further, it is revealed that contrary to previous claims, the many-body effects in these structures are insensitive to temperature. Consequently, such effects cannot account for the observed blue shift of the principal infrared peak as a function of decreasing temperature.