Magnetic multilayers in Ga1-xMn xAs/GaAs struc

Abstract

/2. Ga1–xMn xAs (for x 0.04) has been proved to be an extremely interesting material, for its intrincated transport and magnetic properties. In the first part of this work a structure is considered in which a series of Ga1–xMn xAs layers is grown inside a GaAs quantum well. The electron-electron interaction through a Hartree potential, together with the magnetic interaction with the DMS layers (assumed in the ferromagnetic phase) produces an e effctive potential corresponding to a sequence of small barriers which depend (height and width) on the hole spin orientation. For a large number of such layers it is shown that the model structure approaches a magnetic superlattice. A self-consistent calculation is performed for the electronic structure, resulting into spin-polarized energy levels. The polarized miniband Bloch transport properties are calculated for different structural arrangements. In the second part we calculate the transversal spin polarized current induced by an applied voltage through an AlAs/Ga1–xMn xAs/AlAs double barrier heterostructure (DBH). The magnetic layer is assumed in its metallic and ferromagnetic phase. As a consequence of the magnetic interaction a strong polarization of the hole subbands inside the quantum well. In that case the resonant tunneling occurs at different voltages for different spin orientation (parallel or anti-parallel to the average magnetization of Ga1–xMn xAs) throughout. Based on a many-body field quantization formalism that makes use of the tight binding method we obtain, in an essentially exact way, an analytic expression for the spin polarized tunneling current and the escape rate from the right barrier of the DBH. The characteristic spin polarized I(V) curves, as well as the relaxation times, are obtained for different hole concentrations and magnetic layer widths, providing important informations for the possibility of building spin valves made those materials.]]>

Transport properties of a Ga1-xMn xAs/Ga1-yAl yAs double-barrier

“…As discussed in previous works [13][14][15] the device described here produces a current strongly polarized. Without taken into account the Rashba effect, the polarization is almost total.…”

A selfconsistent calculation of the transport properties of a double barrier spin filter

“…As discussed in previous works [12][13][14] the device described here produces a current strongly polarized. Without taken into account the Rashba effect, the polarization is almost total.…”

The Rashba effect on a double-barrier spin polarizer

“…As discussed in previous works [12][13][14], the device described here produces a current strongly polarized. Without the Rashba effect, the polarization is almost total.…”

“…In previous works [12][13][14], a structure is considered in which a bias is applied through a double barrier of AlAs in the middle of which lies a Ga 1Àx Mn x As quantum well in its metallic ferromagnetic phase. The effects of charge accumulation in the well were considered by a self-consistent calculation of the profile-charge dependence.…”