Spin-polarization effects in homogeneous and non-homogeneous diluted magnetic semiconductor heterostructures

Spin polarization is a key characteristic in developing spintronic devices. Diluted magnetic heterostructures (DMH), where subsequent layers of conventional and diluted magnetic semiconductors (DMS) are alternate, are one of the possible ways to obtain it. Si being the basis of modern electronics, Si or other group-IV DMH can be used to build spintronic devices directly integrated with conventional ones. In this work we study the physical properties and the spin-polarization effects of p-type DMH based in group-IV semiconductors (Si, Ge, SiGe, and SiC), by performing self-consistent (k) over right arrow . (p) over right arrow calculations in the local spin density approximation. We show that high spin polarization can be maintained in these structures below certain values of the carrier concentrations. Full spin polarization is attained in the low carrier concentration regime for carrier concentrations in the DMS layer up to similar to 2.0 x 10(19) cm(-3) for Si and up to similar to 6.0 x 10(19) cm(-3) for SiC. Partial, but still important spin polarization can be achieved for all studied group-IV DMH, with the exception of Ge for carrier concentrations up to 6.0 x 10(19) cm(-3). The role played by the effective masses and the energy splitting of the spin-orbit split-off hole bands is also discussed throughout the paper.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CNPq[550.126/05-8/CTPETRO]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CNPq[303.817/05-4/PQ]

CNPq[304936/2009-0/PQ]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CNPq[303578/2007-6/PQ]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CNPq[577.219/2008-1/JP]

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

CAPES

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

FACEPE[1077-1.05/08/APQ]

Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

FAPESP