Theory and simulation of spin transport in antiferromagnetic semiconductors: Application to MnTe

In this paper we study the parallel spin current in an antiferromagnetic semiconductor thin film where we take into account the interaction between itinerant spins and lattice spins. The spin model is an anisotropic Heisenberg model. Here we use the Boltzmann equation with numerical data on cluster distribution obtained by Monte Carlo simulations and cluster-construction algorithms. We study the cases of degenerate and nondegenerate semiconductors. The spin resistivity in both cases is shown to depend on the temperature, with a broad maximum at the transition temperature of the lattice spin system. The shape of the maximum depends on the spin anisotropy and on the magnetic field. It shows, however, no sharp peak in contrast to ferromagnetic materials. Our method is applied to MnTe. Comparison to experimental data is given.