scholarly journals Spin Dependent Transport through Driven Magnetic System with Aubry-Andre-Harper Modulation

2021 ◽  
Vol 11 (5) ◽  
pp. 2309
Author(s):  
Arpita Koley ◽  
Santanu K. Maiti ◽  
Judith Helena Ojeda Silva ◽  
David Laroze
Keyword(s):  
Spin Polarization ◽  
Magnetic System ◽  
Magnetic Moments ◽  
Tight Binding ◽  
Irradiation Effect ◽  
Spin Dependent Transport ◽  
Magnetic Chain ◽  
Polarization Coefficient ◽  
Dependent Transport ◽  
Energy Channels

In this work, we put forward a prescription of achieving spin selective electron transfer by means of light irradiation through a tight-binding (TB) magnetic chain whose site energies are modulated in the form of well known Aubry–Andre–Harper (AAH) model. The interaction of itinerant electrons with local magnetic moments in the magnetic system provides a misalignment between up and down spin channels which leads to a finite spin polarization (SP) upon locating the Fermi energy in a suitable energy zone. Both the energy channels are significantly affected by the irradiation which is directly reflected in degree of spin polarization as well as in its phase. We include the irradiation effect through Floquet ansatz and compute spin polarization coefficient by evaluating transmission probabilities using Green’s function prescription. Our analysis can be utilized to investigate spin dependent transport phenomena in any driven magnetic system with quasiperiodic modulations.

Spin-dependent transport and spin polarization in coupled quantum wells

2008 ◽  
Vol 104 (6) ◽  
pp. 064321
Author(s):  
Genhua Liu ◽  
Yonghai Chen ◽  
Yu Liu ◽  
Caihong Jia ◽  
Zhanguo Wang
Keyword(s):  
Quantum Wells ◽  
Spin Polarization ◽  
Coupled Quantum Wells ◽  
Spin Dependent Transport ◽  
Dependent Transport

SPIN-DEPENDENT TRANSPORT THROUGH A FINITE INTERACTING QUANTUM DOT WITH INTRADOT SPIN-FLIP SCATTERING

2008 ◽  
Vol 22 (05) ◽  
pp. 323-335
Author(s):  
KAI-HE DING ◽  
ZHEN-GANG ZHU ◽  
XING-HAI LIU
Keyword(s):  
Quantum Dot ◽  
Local Density ◽  
Magnetic Moments ◽  
Spin Valve ◽  
Local Density Of States ◽  
Green Function Method ◽  
Spin Flip ◽  
Spin Dependent Transport ◽  
Valve Effect ◽  
Dependent Transport

Based on the non-equilibrium Green function method, we investigate the spin-dependent transport through a finite interacting quantum dot with intradot spin-flip scattering for non-collinear configuration. It is found that when the intradot spin-flip scattering is applied, the Kondo peaks in the local density of states and the conductance are split, and the splitting peaks are suppressed sharply. By changing the relative orientation of both magnetizations, amplitudes of the splitting peaks appear asymmetric, and reduce with the increasing relative angle θ of the two magnetic moments. It is uncovered that the presence of the spin-flip scattering tends to greatly suppress the spin-valve effect.

Electron-spin polarization in both magnetically and electrically modulated nanostructures

2005 ◽  
Vol 83 (3) ◽  
pp. 219-227
Author(s):  
Mao-Wang Lu
Keyword(s):  
Spin Polarization ◽  
Electron Spin ◽  
High Energy ◽  
Electron Spin Polarization ◽  
Spintronic Devices ◽  
Spin Dependent Transport ◽  
73.40 Gk ◽  
Spin Polarization Effect ◽  
Dependent Transport ◽  
Electric Barrier

We investigate theoretically the spin-dependent transport properties of electrons in realistic magnetic-electric-barrier (MEB) nanostructures produced by the deposition, onto a heterostructure, of a metallic ferromagnetic stripe. We find the degree of electron-spin polarization to be closely tied to the voltage applied to the stripe, despite the fact that this voltage in itself induces no spin-polarization effect. As a positive (negative) voltage is applied, the electron-spin polarization shifts in the low- (high-) energy direction and increases (decreases). Our results imply that the degree of electron-spin polarization can be tuned through the applied voltage. This implication might prove useful in the design and application of spintronic devices based on magnetic-barrier nanostructures. PACS Nos.: 73.40.Gk, 73.23.-b, 75.70.Cn

scholarly journals Electric Field Controlled Itinerant Carrier Spin Polarization in Ferromagnetic Semiconductors

2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Gezahegn Assefa
Keyword(s):  
Electric Field ◽  
Spin Polarization ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Ferromagnetic Semiconductors ◽  
Ferromagnetic Metals ◽  
Spin Dependent Transport ◽  
Diluted Magnetic ◽  
Dependent Transport ◽  
Electrical Manipulation

Electric field control of magnetic properties has been achieved across a number of different material systems. In diluted magnetic semiconductors (DMSs), ferromagnetic metals, multiferroics, etc., electrical manipulation of magnetism has been observed. Here, we study the effect of an electric field on the carrier spin polarization in DMSs ( GaAsMn ); in particular, emphasis is given to spin-dependent transport phenomena. In our system, the interaction between the carriers and the localized spins in the presence of electric field is taken as the main interaction. Our results show that the electric field plays a major role on the spin polarization of carriers in the system. This is important for spintronics application.

Bias-induced reconstruction of hybrid interface states in magnetic molecular junctions

2021 ◽  
Author(s):  
Lingmei Zhang ◽  
Yuanyuan Miao ◽  
Zhipeng Cao ◽  
Shuai Qiu ◽  
Guangping Zhang ◽  
...  
Keyword(s):  
Spin Polarization ◽  
Energy Shift ◽  
Interface States ◽  
Molecular Junctions ◽  
Large Current ◽  
Spin Dependent Transport ◽  
Dependent Transport ◽  
Hybrid Interface ◽  
Current Spin Polarization

Abstract Based on first-principles calculations, the bias-induced evolution of hybrid interface states in π-conjugated tricene and insulating octane magnetic molecular junctions is investigated. Obvious bias-induced splitting and energy shift of the spin-resolved hybrid interface states are observed in the two junctions. The recombination of the shifted hybrid interface states from different interfaces makes the spin polarization around the Fermi energy strongly bias dependent. The transport calculations demonstrate that in the π-conjugated tricene junction, the bias-dependent hybrid interface states work efficiently for large current, current spin polarization, and distinct tunneling magnetoresistance. But in the insulating octane junction, the spin-dependent transport via the hybrid interface states is inhibited, which is only slightly disturbed by the bias. This work reveals the phenomenon of bias-induced reconstruction of hybrid interface states in molecular spinterface devices, and the underlying role of molecular conjugated orbitals in the transport ability of hybrid interface states.

ELECTRON-SPIN POLARIZATION IN BOTH MAGNETICALLY AND ELECTRICALLY-MODULATED NANOSTRUCTURES

2005 ◽  
Vol 12 (01) ◽  
pp. 67-74
Author(s):  
MAO-WANG LU
Keyword(s):  
Spin Polarization ◽  
Electron Spin ◽  
Applied Voltage ◽  
High Energy ◽  
Electron Spin Polarization ◽  
Spin Dependent Transport ◽  
Positive Voltage ◽  
Spin Polarization Effect ◽  
Dependent Transport ◽  
Electric Barrier

We theoretically investigate the spin-dependent transport properties of electrons in realistic magnetic-electric barrier nanostructures, which are produced by the deposition, on top of a heterostructure, of a metallic ferromagnetic stripe with an applied voltage. The degree of the electron-spin polarization is found to be closely associated with this voltage, although the use of applied voltage itself induces no spin polarization effect. As a positive voltage is applied to the stripe the electron-spin polarization shifts towards the low-energy region and increases; it shifts towards the high-energy direction and reduces for a negative applied voltage. These results shown in this work imply that the degree of electron-spin polarization can be tuned by means of an applied voltage on the stripes of system, which may result in a practical voltage-controlled spin filter.

Dynamical Nuclear Polarization

2018 ◽  
Author(s):  
M. M. Glazov
Keyword(s):  
Spin Polarization ◽  
Nuclear Spin ◽  
Nuclear Polarization ◽  
Magnetic Moments ◽  
Nonlinear Effects ◽  
Many Body ◽  
Nuclear Spin Polarization ◽  
Optical Resonances ◽  
Dynamical Nuclear Polarization ◽  
Temperature Concept

The transfer of nonequilibrium spin polarization between the electron and nuclear subsystems is studied in detail. Usually, a thermal orientation of nuclei in magnetic field is negligible due to their small magnetic moments, but if electron spins are optically oriented, efficient nuclear spin polarization can occur. The microscopic approach to the dynamical nuclear polarization effect based on the kinetic equation method, along with a phenomenological but very powerful description of dynamical nuclear polarization in terms of the nuclear spin temperature concept is given. In this way, one can account for the interaction between neighbouring nuclei without solving a complex many-body problem. The hyperfine interaction also induces the feedback of polarized nuclei on the electron spin system giving rise to a number of nonlinear effects: bistability of nuclear spin polarization and anomalous Hanle effect, dragging and locking of optical resonances in quantum dots. Theory is illustrated by experimental data on dynamical nuclear polarization.

scholarly journals Strain Investigation on Spin-Dependent Transport Properties of γ-Graphyne Nanoribbon Between Gold Electrodes

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yun Li ◽  
Xiaobo Li ◽  
Shidong Zhang ◽  
Liemao Cao ◽  
Fangping Ouyang ◽  
...  
Keyword(s):  
Transport Properties ◽  
High Performance ◽  
Density Functional ◽  
Strain Engineering ◽  
Molecular Junctions ◽  
Spin Splitting ◽  
Functional Theory ◽  
Spin Dependent Transport ◽  
The Density Functional Theory ◽  
Dependent Transport

AbstractStrain engineering has become one of the effective methods to tune the electronic structures of materials, which can be introduced into the molecular junction to induce some unique physical effects. The various γ-graphyne nanoribbons (γ-GYNRs) embedded between gold (Au) electrodes with strain controlling have been designed, involving the calculation of the spin-dependent transport properties by employing the density functional theory. Our calculated results exhibit that the presence of strain has a great effect on transport properties of molecular junctions, which can obviously enhance the coupling between the γ-GYNR and Au electrodes. We find that the current flowing through the strained nanojunction is larger than that of the unstrained one. What is more, the length and strained shape of the γ-GYNR serves as the important factors which affect the transport properties of molecular junctions. Simultaneously, the phenomenon of spin-splitting occurs after introducing strain into nanojunction, implying that strain engineering may be a new means to regulate the electron spin. Our work can provide theoretical basis for designing of high performance graphyne-based devices in the future.

scholarly journals Nanodevices engineering and spin transport properties of MnBi2Te4 monolayer

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yipeng An ◽  
Kun Wang ◽  
Shijing Gong ◽  
Yusheng Hou ◽  
Chunlan Ma ◽  
...  
Keyword(s):  
Transport Properties ◽  
Field Effect Transistors ◽  
First Principles Calculations ◽  
Next Generation ◽  
Strong Response ◽  
The Road ◽  
Spin Dependent Transport ◽  
2D Structure ◽  
Filtering Effect ◽  
Dependent Transport

AbstractTwo-dimensional (2D) magnetic materials are essential for the development of the next-generation spintronic technologies. Recently, layered van der Waals (vdW) compound MnBi2Te4 (MBT) has attracted great interest, and its 2D structure has been reported to host coexisting magnetism and topology. Here, we design several conceptual nanodevices based on MBT monolayer (MBT-ML) and reveal their spin-dependent transport properties by means of the first-principles calculations. The pn-junction diodes and sub-3-nm pin-junction field-effect transistors (FETs) show a strong rectifying effect and a spin filtering effect, with an ideality factor n close to 1 even at a reasonably high temperature. In addition, the pip- and nin-junction FETs give an interesting negative differential resistive (NDR) effect. The gate voltages can tune currents through these FETs in a large range. Furthermore, the MBT-ML has a strong response to light. Our results uncover the multifunctional nature of MBT-ML, pave the road for its applications in diverse next-generation semiconductor spin electric devices.

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