Origin of the Anomalous Hall Effect in theFerromagnetic Semiconductor Ga1-xMnxAs

摘要

We present a detailed study of the Hall effect andmagnetoresistance as a function of magnetic field and temperature in aseries of metallic Ga1-xMnxAs samples, with 0.015≤x≤0.08 and Curietemperature TC between 45K and 112K. A contribution to the anomalousHall resistivity which varies as the square of the longitudinal resistivity isidentified. The magnitude of the anomalous Hall conductivity is in goodagreement with the predictions of a Berry phase theory of the anomalousHall effect for x≤0.06. In addition, hole densities are extracted as a functionof x, which are used to compare the measured TC with mean field theorypredicted values. TC is overestimated by the theory at large x, while at low xthe measured TC is significantly larger than predicted.