RESUMO
Theoretical studies on spin-dependent transport in magnetic tunneling diodes with giant Zeeman splitting of the valence band are carried out. The studied structure consists of two nonmagnetic layers CdMgTe separated by a diluted magnetic semiconductor barrier CdMnTe, the hole is surrounded by two p-doped CdTe layers. Based on the parabolic valence band effective mass approximation and the transfer matrix method, the magnetization and the current densities for holes with spin-up and spin-down are studied in terms of the Mn concentration, the well and barrier thicknesses as well as the voltage. It is found that, the current densities depend strongly on these parameters and by choosing suitable values; this structure can be a good spin filter. Such behaviors are originated from the enhancement and suppression in the spin-dependent resonant states.
Assuntos
Manganês/química , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Modelos Químicos , Semicondutores , Simulação por Computador , Desenho Assistido por Computador , Transporte de Elétrons , Desenho de Equipamento , Análise de Falha de Equipamento , Campos Magnéticos , Teoria Quântica , Marcadores de SpinRESUMO
The structural, electronic and magnetic properties of BeSiAs(2) and BeGeAs(2) chalcopyrite ternary compounds doped with manganese were investigated by means of ab initio calculations. It was found that substitution of Be atoms by Mn increases the lattice constants of both compounds that provide acceptable mismatch with conventional Si, Ge and GaAs substrates. In spite of the increase of the spin polarization upon doping, both compounds possess antiferromagnetic (AFM) ordering with the impurity in the group II position whereas ferromagnetic (FM) ordering is obtained in the case of an impurity in the group IV position.
