Hall effect and hole densities in Ga1−xMnxAs

Abstract

By studying the Hall effect in a series of low resistivity Ga1−xMnxAs samples, accurate values for the hole density p, Mn concentration x, and Curie temperature TC are obtained over the range 0.015⩽x⩽0.08. The hole density corresponds to 90% of the Mn concentration at low x, and has a maximum value of 1.0×1027 m−3 when TC=125 K. These data allow the first meaningful comparison of mean field predicted Curie temperatures with experiment over a wide range of x. The theory is in qualitative agreement with experiment, but overestimates TC at large x and underestimates TC at low x.