Spin-polarization effects in homogeneous and non-homogeneous diluted magneticsemiconductor heterostructures

Abstract

Spin polarization is a key characteristic in developing spintronic devices. Diluted magneticheterostructures (DMH), where subsequent layers of conventional and diluted magneticsemiconductors (DMS) are alternate, are one of the possible ways to obtain it. Si being thebasis of modern electronics, Si or other group-IV DMH can be used to build spintronicdevices directly integrated with conventional ones. In this work we study the physicalproperties and the spin-polarization effects of p-type DMH based in group-IVsemiconductors (Si, Ge, SiGe, and SiC), by performing self-consistent calculations in the local spin density approximation. We show that highspin polarization can be maintained in these structures below certain valuesof the carrier concentrations. Full spin polarization is attained in the lowcarrier concentration regime for carrier concentrations in the DMS layer up to ∼ 2.0 × 1019 cm − 3 for Si andup to ∼ 6.0 × 1019 cm − 3 for SiC. Partial, but still important spin polarization can be achieved for all studiedgroup-IV DMH, with the exception of Ge for carrier concentrations up to6.0 × 1019 cm − 3. The role played by the effective masses and the energy splitting of the spin–orbit split-offhole bands is also discussed throughout the paper.