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We theoretically investigate the dwell time for electrons in an antiparallel double $\delta $ -magnetic-barrier nanostructure, which is constructed on the surface of the InAs/Al x In1- x As heterostructure by patterning two ferromagnetic (FM) stripes. It is shown that the dwell time is dependent on electron spins due to the spin–field interaction between spins and magnetic fields. It is also shown that both magnitude and sign of the spin polarization in the dwell time can be modulated by the structural width or magnetic-strength difference between two magnetic barriers, which may give rise to a controllable temporal spin splitter for spintronics device applications.

The dwell time of electrons in a parallel double δ-magnetic-barrier (MB) nanostructure constructed by patterning an asymmetric ferromagnetic stripe on both the top and bottom of an InAs/AlxIn1−xAs heterostructure is calculated. Because the electron spins interact with the structural magnetic fields, the dwell time depends on the electron spins. Moreover, both the magnitude and sign of the spin-polarized dwell time can be modified by changing the magnetic field, the applied voltage, and the separation between the two δ-MBs. The electron spins can thus be separated in the time dimension, and such a magnetic nanostructure could serve as a controllable temporal spin splitter for use in spintronics device applications.

We have theoretically investigated the control of wave-vector filtering (WVF) by introducing δ-doping into a magnetically modulated nanostructure fabricated by depositing ferromagnetic stri...

The magnetically confined semiconductor heterostructure (MCSH) is often used as the momentum filter due to an essentially 2-D process for the electronic tunneling. Taking a typical MCSH into account, we theoretically investigate how to manipulate such momentum filters by the $\delta $ -doping technique. The momentum-filtering efficiency can be tuned because of the $\delta $ -doping dependence of the electron transmission. The involved MCSH can be employed as a controllable momentum filter.

We report on a theoretical study of the giant magnetoresistance (GMR) effect in a δ -doped magnetically confined semiconductor heterostructure nanostructure (MCSHN), which can be realized by depositing two nanosized ferromagnetic (FM) stripes on top and bottom of the semiconductor heterostructure and using the atomic layer doping technique. It is shown that such a nanosystem shows up a sizable GMR effect due to a significant discrepancy in transmission of parallel (P) and antiparallel (AP) magnetization configurations. It is also shown that the MR ratio varies sensitively with the weight and/or position of the δ -doping. Thus, one can conveniently tailor the degree of GMR effect by tuning the δ -doping, and such a nanosystem can be employed as a controllable GMR device for magnetic information storage.

We theoretically investigate Goos-Hänchen (GH) displacement by modelling the spin transport in an archetypal device structure-a magnetically confined GaAs/Al

Based on a composite magnetic–electric-barrier nanostructure, a spin spatial splitter was proposed recently. In order to control the spin-polarized lateral displacement (LD) of electrons, a tunable δ-potential is introduced into this device by the atomic layer doping technique. Theoretical analysis together with numerical simulation shows that both magnitude and sign of spin-polarized LD change dramatically with the height and/or the position of the δ-doping. Consequently, a structurally tunable spin spatial splitter can be achieved for spintronics applications.

We theoretically investigate how to manipulate spin-dependent Goos–Hanchen (GH) shifts by an applied bias in a realistic magnetic-barrier nanostructure, which is experimentally created by depositing a ferromagnetic stripe with perpendicular magnetization on the top of heterostructure. GH shifts of transmitted electron beams are calculated numerically with the help of the stationary phase method. It is shown that both magnitude and sign of spin polarization in GH shifts are closely relative to the applied bias, which can give rise to a bias-controllable spin beam splitter.

We present a theoretical study on the spin-dependent Goos–Hanchen (GH) effect in a two-dimensional electron gas modulated by ferromagnetic and Schottky metal (SM) stripes. The GH shifts for spin electron beams across this device are calculated with the help of the stationary phase method. It is shown that the GH shift of spin-up beam is significantly different from that of spin-down beam, i.e., this device shows up a considerable spin polarization effect in GH shifts of electron beams. It also is shown that both magnitude and sign of spin polarization of GH shifts are closely related to the stripe width, the magnetic strength and the gated voltage under SM stripe. These interesting properties not only provide an effective method of spin injection for spintronics application, but also give rise to a tunable spin beam splitter.

We study how the transmission properties of a two-dimensional electron gas, modulated by a ferromagnetic stripe and a Schottky metal (SM) stripe in a parallel configuration, can be modified by manipulating the voltage applied to the SM stripe. Both the transmission coefficient and conductance of the device are found to be strongly dependent on the electric-barrier height induced by an applied voltage under the SM stripe. Thus, transmission properties of electrons in the device can be conveniently tailored by means of tuning this applied voltage.

We investigate the Goos–Hanchen (GH) effect of spin electron beams in a magnetic-barrier (MB) nanostructure consisting of antiparallel double δ - MBs , which can be experimentally realized by depositing two ferromagnetic (FM) stripes on top and bottom of the semiconductor heterostructure. GH shifts for spin electron beams across this type of MB nanostructures, is derived exactly, with the help of the stationary phase method. It is shown that GH shifts depend strongly on the spin directions for double δ - MBs with unidentical magnetic strengths, giving rise to a considerable spin polarization effect. It also is shown that spin polarization of GH shifts is closely relative to the separation and magnetic-strength difference of two δ - MBs . These interesting properties may provide an alternative scheme to spin-polarize electrons into the semiconductor, and the devices can serve as tunable spin beam splitters.

Recently, an electron-spin filter was proposed by depositing a nanosized ferromagnetic metal stripe and a Schottky normal metal stripe on the top of the semiconductor heterostructure [F. Zhai, H. Q. Xu and Y. Guo, Phys. Rev. B70 (2004) 085308]. This device has a considerable electron-spin polarization and potential application in spintronics. Here we apply a bias to this device and theoretically demonstrate how to manipulate its electron-spin polarization. By numerical simulations, we found that not only the amplitude of the electron-spin polarization but also its sign varies with the bias, giving rise to a bias-tunable spin filter device.

With the help of stationary phase method, we investigate the Goos-Hanchen (GH) effect of electrons in nanostructures consisting of realistic magnetic barriers (MB) created by lithographic patterning of ferromagnetic (FM) or superconducting films. Due to intrinsic symmetry, only nanostructures with symmetric magnetic field possess a considerable spin-dependent GH effect, and GH shifts of transmitted spin beams are found to depend upon the incident angle and the incident energy of electrons as well as the size and position of the FM stripe. These interesting properties may provide an effective scheme to realize spin injection into semiconductor and also give rise to a type of spin beam splitters based on MB nanostructures.

We propose a giant magnetoresistance (GMR) device by depositing nanosized ferromagnetic (FM) and Schottky normal metal (SM) stripes on the top of the GaAs heterostructure. It is shown that this device possesses a considerable GMR effect, whose magnetoresistance (MR) ratio can be up to 106% at a certain energy. It is also shown that the MR ratio depends strongly on the structural parameters and the electrical barrier height induced by the applied voltage to the SM stripe, and thus this device can be used as a tunable GMR device.