Controlled charge and spin current rectifications in a spin polarized device

Patra, Moumita; Maiti, Santanu K.

doi:10.1016/j.jmmm.2019.04.057

Cited by 18 publications

(14 citation statements)

References 66 publications

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“…As the net current through any dephasing lead is zero, the voltage (say) V i of the virtual electrodes can be derived by applying a small bias between the real electrodes with V S = V b and V D = 0 (V S and V D are the voltages associated with S and D). Under this condition, the net transmission probability becomes [29][30][31]40…”

Section: Theoretical Formulation Of Circular Spin Currentmentioning

confidence: 99%

“…The main attention is given in developing a suitable theory for describing circular spin current density, and thus circular current, in presence of dephasing. We introduce dephasing effect by connecting Büttiker probes [27][28][29][30][31] at each lattice sites of the bridging conductor, and it can be assumed as the most convincing and appropriate way to include phase randomization processes in transport phenomena. Instead of Büttiker probes, adding a constant damping factor one can also introduce dephasing into the system, as already reported in few works 5,32,33 , but in this mechanism all the essential features may not be captured.…”

Section: Introductionmentioning

confidence: 99%

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Bias-induced circular spin current: Effects of environmental dephasing and disorder

Patra

Maiti

2019

Phys. Rev. B

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Analogous to circular spin current in an isolated quantum loop, bias induced spin circular current can also be generated under certain physical conditions in a nanojunction having single and/or multiple loop geometries which we propose first time, to the best of our concern, considering a magnetic quantum system. The key aspect of our work is the development of a suitable theory for defining and analyzing circular spin current in presence of environmental dephasing and impurities. Unlike transport current in a conducting junction, circular current may enhance significantly in presence of disorder and phase randomizing processes. Our analysis provides a new spin dependent phenomenon, and can give important signatures in designing suitable spintronic devices as well as selective spin regulations.• Case I -In absence of spin flip transmission: a. When spin flip transmission is absent, the relations between different spin dependent current densities with transmission components are as follows. J i→i+1,↑↑ = T ↑↑ ; J i→i+1,↓↓ = T ↓↓ , and J i→i+1,↑↓ = J i→i+1,↓↑ = T ↑↓ = T ↓↑ = 0 ∀ i. Thus, as an example, we can write these relations for Fig. 2 as: J 1→2,↑↑ = J 2→3,↑↑ = T ↑↑ and J 1→2,↓↓ = J 2→3,↓↓ = T ↓↓ . And, the spin flipped terms are:Here, all the spin dependent current densities in different bonds are conserved.• Case II -In presence of spin flip transmission:a. In presence of spin flip transmission, different components behave as follows. J i→i+1,↑↑ = T ↑↑ ; J i→i+1,↓↓ = T ↓↓ ; J i→i+1,↑↓ = T ↑↓ ; J i→i+1,↓↑ = T ↓↑ ∀ i. Thus, for the two bonds shown in Fig. 2 we get J 1→2,↑↑ = J 2→3,↑↑ = T ↑↑ ; J 1→2,↓↓ = J 2→3,↓↓ = T ↓↓ ; J 1→2,↑↓ = J 2→3,↑↓ = T ↑↓ ; and J 1→2,↓↑ = J 2→3,↓↑ = T ↓↑ . Here individual components are no longer conserved for different bonds.b. Another interesting observation is that for a particular bond J i→i+1,↑↓ becomes identical with * Electronic address: santanu.maiti@isical.ac.in

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Section: Theoretical Formulation Of Circular Spin Currentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Bias-induced circular spin current: Effects of environmental dephasing and disorder

Patra

Maiti

2019

Phys. Rev. B

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“…Now, this spin-dependent transport [ 32 , 55 , 60 , 61 ] behavior can be tuned externally by modifying the characteristics of NM spacer and ferromagnetic layers. The site energies of the NM spacer is altered by cosine modulation following the AAH form [ 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 ], whereas the hopping parameter in ferromagnetic chains is rearranged by Floquet–Bloch anstaz [ 60 , 74 , 75 , 76 , 77 , 78 , 79 ] within a minimal coupling scheme due to light irradiation on them. The Hamiltonian of a layered nanojunction is constructed with the TB approximation [ 31 , 67 ] including only the contribution from the nearest-neighbor hopping (NNH) integral.…”

Section: Introductionmentioning

confidence: 99%

Possible Routes to Obtain Enhanced Magnetoresistance in a Driven Quantum Heterostructure with a Quasi-Periodic Spacer

et al. 2021

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In this work, we perform a numerical study of magnetoresistance in a one-dimensional quantum heterostructure, where the change in electrical resistance is measured between parallel and antiparallel configurations of magnetic layers. This layered structure also incorporates a non-magnetic spacer, subjected to quasi-periodic potentials, which is centrally clamped between two ferromagnetic layers. The efficiency of the magnetoresistance is further tuned by injecting unpolarized light on top of the two sided magnetic layers. Modulating the characteristic properties of different layers, the value of magnetoresistance can be enhanced significantly. The site energies of the spacer is modified through the well-known Aubry–André and Harper (AAH) potential, and the hopping parameter of magnetic layers is renormalized due to light irradiation. We describe the Hamiltonian of the layered structure within a tight-binding (TB) framework and investigate the transport properties through this nanojunction following Green’s function formalism. The Floquet–Bloch (FB) anstaz within the minimal coupling scheme is introduced to incorporate the effect of light irradiation in TB Hamiltonian. Several interesting features of magnetotransport properties are represented considering the interplay between cosine modulated site energies of the central region and the hopping integral of the magnetic regions that are subjected to light irradiation. Finally, the effect of temperature on magnetoresistance is also investigated to make the model more realistic and suitable for device designing. Our analysis is purely a numerical one, and it leads to some fundamental prescriptions of obtaining enhanced magnetoresistance in multilayered systems.

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“…So far, various simple and complex molecular structures have been investigated theoretically for modulat-ing the rectification performance. For instance, molecular wires 4 , complex molecular structure with metallic electrodes 17 , quantum wires with correlated site potentials 22,23 , DNA molecular system with Fibonacci sequence 24 , etc. The rectification behavior has also been tested experimentally for several molecular systems, such as symmetric tetraphenyl and non-symmetric diblock dipyrimidinyldiphenyl molecules 9 , molecular rods 25 , single melamine molecule adsorbed on a Cu(100) surface 26 , etc.…”

Section: Introductionmentioning

confidence: 99%

Enhanced current rectification in graphene nanoribbons: Effects of geometries and orientations of nanopores

Majhi,

Ganguly,

Maiti

2021

Preprint

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We discuss the possibility of getting rectification operation in graphene nanoribbon (GNR). For a system to be a rectifier, it must be physically asymmetric and we induce the asymmetry in GNR by introducing nanopores. The rectification properties are discussed for differently structured nanopores. We find that shape and orientation of the nanopores are critical and sensitive to the degree of current rectification. As the choice of Fermi energy is crucial for obtaining significant current rectification, explicit dependence of Fermi energy on the degree of current rectification is also studied for a particular shape of the nanopore. Finally, the role of nanopore size and different spatial distributions of the electrostatic potential profile across the GNR are discussed. Given the simplicity of the proposed method and promising results, the present proposition may lead to a new route of getting current rectification in different kinds of materials where nanopores can be formed selectively.

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Controlled charge and spin current rectifications in a spin polarized device

Cited by 18 publications

References 66 publications

Bias-induced circular spin current: Effects of environmental dephasing and disorder

Bias-induced circular spin current: Effects of environmental dephasing and disorder

Possible Routes to Obtain Enhanced Magnetoresistance in a Driven Quantum Heterostructure with a Quasi-Periodic Spacer

Enhanced current rectification in graphene nanoribbons: Effects of geometries and orientations of nanopores

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