Exchange- and correlation-induced charge transfer observed in independently contacted triple-quantum-well structures.

Abstract

There have been predictions that for closely spaced two-dimensional electron gases (2DEG's), charge transfer between the 2DEG's can arise from electron interactions due to exchange and correlation [Ruden and Wu, Appl. Phys. Lett. 59, 2165 (1991)]. In this study, we are able to determine accurately the charge in each of the 2DEG's of a triple-quantum-well structure. The results demonstrate that as the charge in one 2DEG is reduced, by applying a negative gate voltage the adjacent layer can gain charge; thus charge is effectively transferred between the 2DEG's. This type of charge transfer cannot be explained by a simple noninteracting model of the structure, but can be modeled by including intralayer electron interactions in the form of exchange and correlation correction terms within the local-density approximation. The inclusion of these many-body interaction terms into our model leads to a good qualitative agreement with the experimental data, confirming that the origin of the charge transfer is electron interactions. \textcopyright{} 1996 The American Physical Society.