Enhanced Hall slope in wideAlxGax−1Asparabolic wells

Abstract

We report measurements of the Hall effect in $1000--4000\phantom{\rule{0.3em}{0ex}}\mathrm{\AA{}}$ wide ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{x\ensuremath{-}1}\mathrm{As}$ parabolic wells with quasi-two-dimensional electrons and holes in a perpendicular magnetic field. Above a critical magnetic field $Bg3T$, the Hall resistance for wide parabolic wells is found to be enhanced when the temperature decreases. We attribute this enhanced Hall slope to a carrier density effect. The Hartree and exchange-correlation terms produce a strong variation of the potential-well shape. The width of the electronic and hole slabs shrinks as the magnetic field is increased, which leads to the redistribution of the charge between the well and impurity layer.