Analysis of the ground-state properties of biased double quantum wells by a relaxation-variational method

M. O. Vassell and Johnson Lee
Phys. Rev. B 44, 10736 – Published 15 November 1991

Abstract

The ground-state energy and certain effects of the electron-hole Coulomb interaction in coupled double quantum wells are analyzed by evolving the pair envelope wave function in imaginary time, or equivalently relaxing the wave function in real time. The ground-state energies and envelope wave functions for noninteracting pairs are calculated by a pure relaxation method, and those for interacting electron-hole pairs by a combined relaxation-variational method. The 1s-exciton binding energies are estimated from the difference of the two sets of calculated energies. The excitonic system is described by a two-band effective-mass model in which a 1s variational ansatz is used to average out the in-plane relative motion. Total pair energies, binding energies, variational parameters, and pair probability densities are analyzed as functions of applied longitudinal electric field. All, except the probability, are compared for various barrier thicknesses as well. The characteristic redshift of the quantum-confined Stark effect is reproduced, and the expected decrease of binding energies with increasing field strength is observed for both heavy-hole and light-hole states. As functions of the barrier thickness, the binding energies and variational parameters pass through minima in the 15–25-Å range. Finally, significant migration of carriers is predicted to occur in the formation of the dipole moment in coupled double quantum wells.

  • Received 11 January 1991

DOI:https://doi.org/10.1103/PhysRevB.44.10736

©1991 American Physical Society

Authors & Affiliations

M. O. Vassell and Johnson Lee

  • GTE Laboratories Incorporated, 40 Sylvan Road, Waltham, Massachusetts 02254

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Issue

Vol. 44, Iss. 19 — 15 November 1991

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