Search

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.

We theoretically explore dwell time for electrons in a semiconductor microstructure, which is constructed on the surface of the InAs/Al x In1- x As heterostructure by patterning a ferromagnetic (FM) stripe and a Schottky-metal (SM) stripe in a parallel configuration. Dwell time is found to be dependent on electron spins. Spin-polarized dwell time can be controlled by changing an applied voltage to SM stripe. Thus, electron spins can be separated in time dimension, and such a semiconductor microstructure can be used as an electrically tunable 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...

Based on a magnetically confined GaAs/Al x Ga1– x As microstructure modulated by spin-orbit coupling (SOC), we propose a controllable electron-spin filter for spintronics applications. This device operates due to both Zeeman interaction and Rashba or Dresselhaus SOC. Its spin polarization can be tuned by changing interfacial confining electric field or engineering strain.

The dwell time and spin polarization (SP) of electrons tunneling through a parallel double δ-magnetic-barrier nanostructure in the presence of a bias voltage is studied theoretically in this work. This nanostructure can be constructed by patterning two asymmetric ferromagnetic stripes on the top and bottom of InAs/Al x In1 – x As heterostructure, respectively. An evident SP effect remains after a bias voltage is applied to the nanostructure. Moreover, both magnitude and sign of spin-polarized dwell time can be manipulated by properly changing the bias voltage, which may result in an electrically-tunable temporal spin splitter for spintronics device applications.

We report a theoretical investigation on Goose-Hänchen (GH) effect for spin electrons across a magnetically confined GaAs/AlxGa1-xAs microstructure modulated by spin-orbit coupling [(SOC), including Rashba and Dresselhaus types]. An intrinsic symmetry in the device is broken by SOC, which gives rise to a considerable spin polarization effect in GH shifts of electrons. Both magnitude and direction of spin polarization can be manipulated by Rashba or Dresselhaus SOC, i.e., interfacial confining electric field or strain engineering. Based on such a semiconductor microstructure, a controllable spatial spin splitter can be proposed for spintronics applications.

Semiconductor-based magnetoresistance (MR) device has many advantages such as high MR ratio at low switching magnetic field, but electron spins were ignored completely in previous researches. Electron spins should impact on performance of semiconductor-based MR device, as electron spins interact with magnetic fields. By considering a semiconductor microstructure constructed on GaAs/AlxGa1-xAs heterostructure by patterning two asymmetric ferromagnetic (FM) stripes, we theoretically explore effect of electron spins on semiconductor-based MR device. An interesting spin splitting effect is found in semiconductor-based MR device. Both magnitude and sign of spin splitting effect can be modified by applying a negative voltage. These findings may be helpful for designing semiconductor-based MR devices.

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 theoretically investigate the control of spin-polarized dwell time by δ-doping in a parallel double δ-magnetic-barrier nanostructure, which can be realized experimentally by depositing two asymmetric ferromagnetic stripes at the top and bottom of an InAs/Al x In1−x As heterostructure, respectively. Dwell time is still spin-polarized even if a δ-doping is included inside. Both the magnitude and the sign of the spin-polarized dwell time can be manipulated by changing the weight or position of δ-doping. Therefore, this nanostructure can be employed as a structurally controllable temporal spin splitter for spintronic device applications.

A magnetoresistance (MR) device was proposed by depositing two parallel ferromagnetic stripes on top and bottom of a semiconductor heterostructure [Solid State Commun. 141 (2007) 248]. In order to manipulate its performance, we dope a tunable δ-potential into the device by atomic layer doping technique. Transmission, conductance and MR ratio are calculated for the δ-doped MR device. It is confirmed that an obvious MR effect still exists in the device even though a δ-doping is comprised. Results show that the MR ratio varies intensely with the weight and/or the position of the δ-doping. Therefore, one can manipulate structurally the MR device by altering the δ-doping, and a tunable MR device can be obtained for magnetic information storage.

We theoretically explore to separate electron-spins by dwell time of electrons through a magnetic microstructure with a δ-doping, which is fabricated on surface of InAs/AlxIn1-xAs heterostructure by patterning a ferromagnetic (FM) stripe. It is shown that dwell time is spin related due to both spin-field interaction and broken symmetry. It is also shown that spin-polarized dwell time can be manipulated structurally because of δ-doping dependent effective potential. Therefore, electron spins can be separated in time dimension and such a magnetic microstructure can serve as a controllable temporal spin splitter.

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

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.

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.

A controllable spin filter is proposed by theoretically investigating spin polarization in a magnetic microstructure constructed on surface of GaAs/AlxGa1-xAs heterostructure by patterning a horizontally-magnetized ferromagnetic stripe. Due to a broken intrinsic symmetry by spin-orbit coupling, a spin polarization effect appears in the magnetic microstructure. Degree of spin polarization can be modified by changing strength of spin-orbit coupling, which may be helpful for design of controllable spin-polarized source.

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.

We theoretically investigate Goos-Hanchen (GH) displacement by modelling the spin transport in an archetypal device structure-a magnetically confined GaAs/Al x Ga1-x As nanostructure modulated by spin-orbit coupling (SOC). Both Rashba and Dresselhaus SOCs are taken into account. The degree of spin-polarized GH displacement can be tuned by Rashba or Dresselhaus SOC, i.e. interfacial confining electric field or strain engineering. Based on such a semiconductor nanostructure, a controllable spatial spin splitter can be proposed for spintronics applications.

We report a theoretical study on spin-polarized transport in a δ-doped magnetic-electric-barrier nanostructure, which can be realized in experiments by depositing two ferromagnetic stripes on top and bottom of a semiconductor heterostructure under an applied voltage and by using atomic layer doping technique. The spin-polarized behavior of the electron in this device is found to be quite sensitive to the δ-doping. One can conveniently tune the degree of the electron spin polarization by adjusting the weight and/or position of the δ-doping. Thus, the involved nansosystem can be employed as a controllable spin filter, which may be helpful for exploiting new spin-polarized source for spintronics applications.

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.

The giant magnetoresistance (GMR) effect in a device, composed of nanosized ferromagnetic (FM)-Schottky metals (SM) and semiconductor heterostructure, is investigated theoretically. Experimentally, this GMR device can be realized by the deposition of two parallel FM strips and a SM stripe on the top of a GaAs heterostructure. It is shown that the GMR effect ascribes a significant electron transmission difference between the parallel and antiparallel magnetization configurations of two FM stripes in the device. It is also shown that the magnetoresistance (MR) ratio depends strongly on the magnetic intensity of the magnetic barrier (MB) and the electric-barrier (EB) height induced by an applied voltage to the SM stripe. Thus, this device can be used as a tunable GMR one, whose MR ratio can be switched by adjusting the applied voltage under the SM stripe or by changing the magnetic strength of the MB.