Hanle effect and spin-dependent recombination at deep centers in GaAsN

Abstract

The peculiarities of Hanle effect (i.e., the depolarization of edge photoluminescence in a transverse magnetic field) in semiconductors, brought about by spin-dependent recombination of free electrons with deep paramagnetic centers, have been investigated in GaAs 0.979 N 0.021 alloy at room temperature. The measured Hanle curve consists of narrow and wide parts with the widths at the half-height being ∼100 and ∼120000 G. The difference between the widths by three orders of magnitude results from strongly differing spin lifetimes of bound and free electrons, T sc and T s . Using g -factor values +2 and +1 for bound and free electrons, respectively, we have found that T sc ≈700 ps and T s ≈2 ps. Thus obtained values of T sc and T s allow us to describe theoretically the experimental Hanle curve as well as its dependence on the pump intensity.