LASER INDUCED METAL INSULATOR TRANSITION THROUGH EXCITON MECHANISM IN QUANTUM WELL SYSTEMS

Abstract

Within the effective mass approximation, the binding energies of a Wannier exciton in a GaAs-Ga 1-x Al x As quantum well in an electric field are investigated using a variational method. The binding energiesare obtained upon illlumination by laser radiation. The binding energy decreases as the well size increases when the size of the well is beyond 50 Å. The above behavior is for a quantum well of finite confinement. We have investigated the metal-insulator transition in such a system and report the values of critical concentrations of excitons at which metal-insulator transition occurs for different well dimensions. The calculated diamagnetic susceptibility shows the catastrophic behavior at the critical concentration.