Experimental evidence of a Mott transition in highly doped two-dimensional confined structures

Abstract

Mott transition in a two-dimensional electron gas in a doped $\mathrm{Ga}\mathrm{As}∕\mathrm{Al}\mathrm{Ga}\mathrm{As}$ quantum well is experimentally studied. The impurity band is observed at a doping level up to ${10}^{18}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$. This value is two orders of magnitude higher than the Mott transition in bulk GaAs (about ${10}^{16}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$). This high density Mott transition is explained by a quantitative model involving the donor distribution in the wells.