Spin polarized quantum pump effect in zigzag graphene nanoribbons

Grichuk, E. S.; Manykin, E. A.

doi:10.1134/s0021364011070058

Cited by 13 publications

(17 citation statements)

References 25 publications

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“…Here we apply two static gate voltages V g and V g to modulate the on-site energies in these two regions of the GNR independently to facilitate the identification of the influence of the pumping from different regions. Following previous investigations in the literature, [16][17][18][19][20][21][22][23][24][25][26][27][28] we adopt the dc and ac gate potential with abrupt edges. 62 Exploiting the nonequilibrium Green's function method, 60 the time-averaged current can be written as (the current flowing from left to right is defined to be positive)…”

Section: Model and Formalismmentioning

confidence: 99%

“…15 Recently, the quantum charge and spin pumping in GNRs has also aroused growing attention. [16][17][18][19][20][21][22][23][24][25][26][27][28] Most of these studies focus on the pumping involving more than one time-dependent parameter, [16][17][18][19][20][21][22][23][24][25] partially because the single-parameter pumping is only possible beyond the adiabatic approximation and thus needs a more complex theoretical tool. 39 Nevertheless, the single-parameter pumping is more favorable to the application, since the reduction in the number of necessary contacts makes the scalable and low-dissipative device more promising.…”

Section: Introductionmentioning

confidence: 99%

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Single-parameter quantum charge and spin pumping in armchair graphene nanoribbons

Zhou

2012

Phys. Rev. B

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We investigate quantum charge and spin pumping in armchair graphene nanoribbons under a single ac gate voltage connected with nonmagnetic/ferromagnetic leads via the nonequilibrium Green's function method. In the case of nonmagnetic leads, where only part of the nanoribbon is subject to an ac gate voltage to break the left-right spatial symmetry, we discover that peaks of the charge pumping current appear at the Fermi energies around the sub-band edges in the ac-field-free region of the nanoribbon. In the case of ferromagnetic leads with the lead magnetizations being antiparallel to break the left-right symmetry, similar peaks appear in the spin pumping current when the Fermi energies are around the edges of the the majority-spin sub-bands in the ferromagnetic leads. All these peaks originate from the pronounced symmetry breaking in the transmissions with energies being around the corresponding sub-band edges. Moreover, we predict a pure spin current in the case of ferromagnetic leads with the whole graphene nanoribbon under an ac gate voltage. The ac-field-strength and ac-field-frequency dependencies of the pumping current are also investigated with the underlying physics revealed.

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Section: Model and Formalismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Single-parameter quantum charge and spin pumping in armchair graphene nanoribbons

Zhou

2012

Phys. Rev. B

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“…On the other hand, controlling of Van-Hove singularities, ribbon size, the edge structure and also defects make graphene nanoribbons (GNR) and also nanotubes as the appropriate candidates for enhanced pumped current [14][15][16][17][18][19] . Furthermore, spin current in monolayer graphene has been also proposed to generate by application of two oscillating gate voltages through the adiabatic quantum pumping in some special Fermi energies 8 .…”

Section: Introductionmentioning

confidence: 99%

Nonadiabatic pure spin pumping in zigzag graphene nanoribbons with proximity induced ferromagnetism

Cheraghchi

2016

Journal of Magnetism and Magnetic Materials

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By combining Floquet theory with Green's function formalism, we present non-adiabatic quantum spin and charge pumping through a zigzag ferromagnetic graphene nanoribbon including a doublebarriers structure driven weakly by two local ac gate voltages operating with a phase-lag. Over a wide range of Fermi energies, interesting quantum pumping such as i) pure spin pumping with zero net charge pumping, ii) pure charge pumping and iii) fully spin polarized pumping can be achieved by tuning and manipulating driving frequency in the non-adiabatic regime. Spin polarized pumping which is measurable using the current technology depends on the competition between the energy level spacing and driving frequency.

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“…In particular, the important role of the Klein tunneling and evanescent modes was stressed [19, 20,21]. The potential use of a quantum pump effect in graphene-based spintronics was also discussed [23,24,25,26,27,28,29].…”

Section: Introductionmentioning

confidence: 99%

Adiabatic quantum pumping in graphene with magnetic barriers

Grichuk

Manykin

2013

Eur. Phys. J. B

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We study an adiabatic quantum pump effect in a two terminal graphene device with two oscillating square electric barriers and a stationary magnetic barrier using the scattering matrix approach. The model employs the low-energy Dirac approximation and incorporates the possible existence of a finite band gap in graphene spectrum. We show that in this case valley-polarized and pure valley currents can be pumped due to the valley symmetry breaking. For a δ-function magnetic barrier we present analytical expressions for bilinear total and valley pumping responses. These results are compared to numerical ones for a double δ-function, a square and a triple square magnetic barriers.

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Spin polarized quantum pump effect in zigzag graphene nanoribbons

Cited by 13 publications

References 25 publications

Single-parameter quantum charge and spin pumping in armchair graphene nanoribbons

Single-parameter quantum charge and spin pumping in armchair graphene nanoribbons

Nonadiabatic pure spin pumping in zigzag graphene nanoribbons with proximity induced ferromagnetism

Adiabatic quantum pumping in graphene with magnetic barriers

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