Spin-dependent tunneling in modulated structures of (Ga,Mn)As

A model of coherent tunneling, which combines multiorbital tight-binding approximation with Landauer-Buttiker formalism, is developed and applied to all-semiconductor heterostructures containing (Ga,Mn)As ferromagnetic layers. A comparison of theoretical predictions and experimental results on spin-dependent Zener tunneling, tunneling magnetoresistance, and anisotropic magnetoresistance is presented. The dependence of spin current on carrier density, magnetization orientation, strain, voltage bias, and spacer thickness is examined theoretically in order to optimize device design and performance.