Large anomalous Hall resistance of pair δ-doped GaAs structures grown by molecular-beam epitaxy

Abstract

Beryllium/silicon pair δ-doped GaAs structures grown by molecular-beam epitaxy exhibit a Hall resistance which has a nonlinear dependence on the applied magnetic field and which is strongly correlated to the negative magnetoresistance observed under the applied magnetic field parallel to the δ-doped layers. Dependence of the occurrence of the nonlinear Hall resistance on the growth condition is investigated. A significantly large increase in both the magnitude and the nonlinearity of the Hall resistance is observed from samples whose GaAs buffer layers are grown under the condition of a low As∕Ga flux ratio. Reflection high energy electron diffraction and electron microscope observations show that a faceted surface develops with the growth and postgrowth annealing of a GaAs buffer layer under the condition of a low As flux. From samples which have only Si δ-doped layers and exhibit the n-type conduction, such nonlinear Hall resistance is not observed. The nonlinearity of the Hall resistance of Be∕Si pair δ-doped structures depends on the single parameter B∕T, where B and T are the applied magnetic field and the temperature, respectively. Based on these results, it is suggested that the nonlinear Hall resistance of Be∕Si pair δ-doped structures is the anomalous Hall effect caused by localized spins in δ-doped layers.