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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.

We theoretically investigate how to manipulate the wave-vector filtering effect by δ-doping for electrons in a magnetically and electrically confined semiconductor heterostructure, which can be constructed by patterning a ferromagnetic stripe and a Schottky-metal stripe in a parallel configuration on the surface of the GaAs/AlxGa1−xAs heterostructure. The δ-doping dependent transmission is calculated by exactly solving the Schrodinger equation with the help of an improved transfer matrix method. An appreciable wave-vector filtering effect is revealed. Its wave-vector filtering efficiency is found to be tunable by changing the weight or position of the δ-doping. Thus, a structurally controllable momentum filter can be obtained for nanoelectronics 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.

Based on antiparallel asymmetric double δ-magnetic-barrier semiconductor microstructure constructed on the surface of GaAs/Al1-xGaxAs heterostructure by patterning two ferromagnetic stripes, an electron-momentum filter was proposed recently. We further explore the effect of a δ-potential realized by the atomic-layer doping technique on this filter device. It is shown that this filter is sensitive to the δ-potential because the effective potential experienced by electrons in the device depends on the δ-potential. It is also shown that both magnitude and sign of wave-vector filtering efficiency can be tuned by adjusting weight or position of the δ-potential. Therefore, a controllable electron-momentum filter may be obtained for nanoelectronics device 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.

We theoretically investigate how to modulate spin-dependent lateral shifts by the spin-orbit coupling (SOC) in a hybrid magnetic-electric-barrier (MEB) nanostructure, which can be experimentally realized by depositing a ferromagnetic (FM) stripe and a Schottky metal (SM) stripe on the top and bottom of the semiconductor heterostructure, respectively. Two kinds of ROCs, Rashba SOC (RSOC) and Dresselhaus SOC (DSOC), are taken into account fully. The Schrodinger equation of the spin electron in the hybrid MEB nanostructure is exactly solved by using the improved transfer-matrix method (ITMM), and the lateral shift and its spin polarization are numerically calculated with the help of the stationary phase method (SPM). Theoretical analysis indicates that the spin polarization effect in the lateral shift still exists in the hybrid MEB nanostructure when the SOCs are considered. Numerical simulations show that both magnitude and sign of the spin polarization effect in lateral shifts vary strongly with the strengths of RSOC and DSOC. These interesting features may offer an effective means to control the behavior of spin-polarized electrons in the semiconductor nanostructure, and such a hybrid MEB nanostructure serves as a SOC-manipulable spatial spin splitter for spintronic applications.

We theoretically explore to manipulate the electron-spin polarization by a δ-potential in 3-layered semiconductor heterostructure modulated by the Rashba spin-orbit-coupling. An obvious electron-spin polarization effect still exists even if the δ-potential is embedded inside. Both size and sign of the electron-spin polarization can be tuned by changing the weight or position of the δ-potential. Therefore, a controllable spin filter can be obtained for spintronics device applications.

We report a theoretical exploration on the control of the Dresselhaus －spin-orbit －coupling (SOC) induced spin polarization via the δ-doping for electrons in the 3-layered semiconductor heterostructure (3-LSH). It is shown that an obvious electron-spin polarization effect still exists when a δ-doping is introduced inside. Moreover, both magnitude and sign of the spin polarization can be controlled by adjusting the weight or position of the δ-doping. Therefore, spin-polarized electrons can be manipulated by the δ-doping technique, and the considered 3-LSH can be used as a structurally-controllable spin filter, which may be helpful for spintronics device applications.

We propose to separate electron-spins by transmission time for electrons across a semiconductor microstructure. By calculating dwell time of electrons in a realistic magnetic microstructure, transmission time is found to be spin related, electron spins are, therefore, separated in time dimension. Besides, both magnitude and sign of spin-polarized dwell time can be manipulated by an applied voltage, which may give rise to an electrically-controllable temporal spin splitter for spintronics device applications.

Considering Dresselhaus-type spin–orbit coupling (SOC), we theoretically investigate spin-polarized transport in a 3-layered semiconductor heterostructure, InSb/InxGa1-xAs/GaSb. Adopting improved transfer matrix method to solve Schrodinger equation, electronic transmission coefficient is obtained exactly, and then spin polarization ratio is evaluated. An appreciable electron-spin polarization effect by the Dresselhaus-SOC appears in this layered semiconductor heterostructure. Spin polarization is associated closely with in-plane wave vector, incident direction and SOC strength. In particular, both magnitude and sign of spin polarization are manipulated by strain engineering or an appropriate intermediate-layer. Therefore, such a 3-layered semiconductor heterostructure can serve as a controllable spin filter for spintronics device applications.

In layered semiconductor heterostructure, there exists spin-orbit coupling (SOC), which can induce electron-spin polarization. Considering a realistic 3-layered semiconductor heterostructure, InSb/InxGa1-xAs/GaSb, we present a theoretical study of spin polarized transport by the Rashba-SOC type. An obvious electron-spin polarization effect is found in such a 3-layered system, and its degree is related to in-plane wave vector, Rashba-SOC strength and intermediate-layer parameters. Both magnitude and sign of spin polarization can be manipulated by tuning interfacial confining electric field or fabricating intermediate layer properly. These interesting features may be useful for exploring new way of spin injection and designing controllable spin filter for spintronics applications.

By means of a hybrid magnetic–electric barrier (MEB) on the top of the semiconductor InAs/AlxIn1−xAs heterostructure, a spin filter can be obtained. In this work, we introduce a δ-doping into this MEB device by molecular beam epitaxy or metal-organic chemical-vapor deposition, to manipulate the spin filtering. With the help of the improved transfer-matrix method and Landauer–Bűttiker theory, transmission coefficient, conductance and spin polarization are calculated for the electrons across this device. Due to spin-field interaction between electron spins and magnetic fields, an obvious spin filtering effect remains in the device even if a δ-doping is included inside. The behavior of spin-polarized electrons is related closely to the δ-doping, due to the strong dependence of the effective potential experienced by the electrons on such a doping. Degree of spin polarization can be manipulated by properly adjusting weight or position of the δ-doping, which gives rise to a structurally controllable spin filter.

A giant magnetoresistance (GMR) device formed by depositing two parallel nanosized ferromagnetic strips on top of a semiconductor heterostructure has been proposed theoretically (Zhai et al. in Phys Rev B 66:125305, 2002). For the sake of manipulating its performance, we introduce a tunable δ-potential into this device with the help of atomic-layer doping techniques such as molecular beam epitaxy (MBE) or metal-organic chemical-vapor deposition. We investigate theoretically the impact of such δ-doping on the magnetoresistance ratio (MR) of the GMR device. We find that, although the δ-doping is embedded in the device, a considerable GMR effect still exists due to the significant difference in electronic transmission between parallel (P) and antiparallel (AP) configurations. Moreover, the calculated results show that the MR of the GMR device varies sensitively with the weight and/or position of the δ-doping. Thus, the GMR device can be controlled by changing the δ-doping to obtain an adjustable GMR device for magnetoelectronics applications.

We report on a theoretical study of the influence of a δ-doping on a giant magnetoresistance (GMR) device based on a magnetically confined GaAs/AlxGa1⿿xAs heterostructure. The δ-doping dependent transmission and conductance of the device are calculated. It is shown that there still exists an obvious GMR effect even the inclusion of a δ-doping. It is also shown that the magnetoresistance ratio (MR) of the device can be switched by changing the weight and/or position of the δ-doping. These interesting features provide an alternative way to manipulate a GMR device, and the structure can be employed as a structurally controllable GMR device for magnetoelectronics applications.

Wave vector filtering effect is explored for electrons in magnetically and electrically confined semiconductor heterostructure, which can be realized experimentally by depositing a ferromagnetic stripe and a Schottky metal stripe in parallel configuration on the surface of [Formula: see text] heterostructure. Adopting improved transfer matrix method to solve Schrödinger equation, electronic transmission coefficient is calculated exactly, and then wave vector filtering efficiency is obtained by differentiating transmission probability over longitudinal wave vector. An obvious wave vector filtering effect appears, due to an essentially two-dimensional process for electron transmission through a magnetic nanostructure. Besides, wave vector filtering efficiency is associated closely with width, position and externally applied voltage of Schottky metal stripe, which makes wave vector filtering effect become controllable and results in a manipulable momentum filter for nanoelectronics.

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.

A magnetoresistance device was proposed by patterning two asymmetric ferromagnetic stripes on top and bottom of the GaAs/AlxGa1-xAs heterostructure. To control its performance, a tunable δ-potential is introduced inside this device by wire-like doping. Adopting transfer matrix method and Landauer-Buttiker conductance theory, Schrodinger equation is solved analytically and δ-doping dependent transmission, conductance and magnetoresistance ratio are calculated. An obvious magnetoresistance effect still stays in this device, due to existence of transmission difference between parallel and antiparallel configurations independent of δ-doping. However, its magnetoresistance ratio can be tuned by changing weight or position of δ-doping. These interesting results not only propose an alternative scheme to manipulate magnetoresistance device, but also a structurally-controllable magnetoresistance device can be obtained for magnetic information storage.

We theoretically investigate modulation of a tunable δ-potential to the lateral displacement of electrons across a magnetically modulated semiconductor nanostructure. Experimentally, this nanostructure can be produced by depositing a nanosized ferromagnetic stripe with in-plane magnetization on top of a semiconductor heterostructure, while the δ-potential can be realized by means of the atomic layer doping technique. Theoretical analysis reveals that this δ-doping can break the intrinsic symmetry in nanostructure and a considerable spin polarization in the lateral displacement will appear. Numerical calculations demonstrate that both magnitude and sign of spin polarization can be manipulated by changing the height and/or position of the δ-doping, giving rise to a structurally tunable spin spatial splitter.