Electron-spin polarization by resonant tunneling

Abstract

The spin-dependent electron resonant tunneling through nonmagnetic III-V semiconductor asymmetric double barriers is studied theoretically within the envelope function approximation and the Kane model for the bulk. It is shown, in particular, that an unpolarized beam of conducting electrons can be strongly polarized, at zero magnetic field, by a spin-dependent resonant tunneling, due to the Rashba mesoscopic spin-orbit interaction. The electron transmission probability is calculated as a function of the electron's energy and angle of incidence. Specific results for tunneling across lattice matched politype Ga 0.47 In 0.53 As/InP/Ga 0.47 In 0.53 As/ GaAs 0.5 Sb 0.5 /Ga 0.47 In 0.53 As double barrier nanostructures show, for instance, sharp spin-split resonances, corresponding to resonant tunneling through spin-orbit split quasibound ground and excited electron states ͑qua-sisubbands͒. The calculated polarization of the transmitted beam in resonance with the second quasisubband shows that polarization bigger than 50% can be achieved with this effect.

Rashba effect and magnetic field in semiconductor quantum wires

“…7,8,9,10 This is the basis of the spin dependent field-effect-transistor (spinFET) earlier discussed theoretically by Datta and Das. 11 Numerous theoretical spintronic devices have been proposed using interference, 12,13,14,15 resonant tunneling, 16,17,18,19 ferromagnet-semiconductor hybrid structures, 20,21,22,23 multiterminal geometries, 24,25,26,27 and adiabatic pumping. 28 Magnetic field effects on the transport properties in 2D systems with SOI have been investigated theoretically 29,30,31 as well as experimentally 7,8,9,10,32,33 .…”

Universal Rashba spin precession of two-dimensional electrons and holes

“…A lot of progress in the field has been stimulated by the exploitation of spin precession due to Rashba spin-orbit (SO) coupling in 2D systems both for electrons [3][4][5] and for holes [6]. A prominent example is the spin-controlled field-effect transistor (spin FET) introduced by Datta and Das [7], followed by more recent proposals for novel devices utilizing Rashba SO coupling [8]. Both in the original [7] and most subsequent [9][10][11][12][13][14] works, a quasionedimensional (1D) confinement was considered essential for proper spin-FET action.…”

“…A nice proposal, which exploits tunability of Rashba SO coupling, to overcome the detrimental effects due to scattering processes is presented in the last paper of Ref. [8].…”

Spin-dependent conductance in nonmagnetic InGaAs asymmetric double barrier devices

“…Besides the spin transistor proposed by Data and Das [1], which is based on the Rashba spin-orbit term, of importance to the spintronics development, there have been, more recently, different proposals of nonmagnetic semiconductor spin filter devices [2,3,4]. However, in order to fabricate them, further investigations are necessary in order to test these ideas in different structures and device geometries.…”