Semiconductor–metal transition in a square quantum wire system

Semiconductor–metal transition in a square quantum wire of the GaAs/GaAlAs system is investigated within the effective mass approximation. Vanishing of the donor ionization energy as a function of well width and donor concentration suggests that no transition is possible below a well width of View the MathML source. Critical impurity concentrations at which the transition occurs increase with reduction in well width. The effects of Anderson localization and correlation in the Hubbard model are included in a simple way. In general, the critical concentration is one order higher in the square quantum wire system when compared to a quantum well case for lower well widths. When well width is increased it reaches the bulk value in both the cases. The critical concentration is enhanced when a random distribution of impurities is considered.