Enhancing single-parameter quantum charge pumping in carbon-based devices

Torres, Luis E. F. Foa; Calvo, Hernán L.; Rocha, C. G.; Cuniberti, Gianaurelio

doi:10.1063/1.3630025

Cited by 58 publications

(40 citation statements)

References 43 publications

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“…The tight-binding version 18 of this method is suitable for studying ac driving of smaller carbon-based conductors, such as ribbons with a size of only a few lattice constants 23 or nanotubes. 24,25 Via time-dependent density functional theory, it can be generalized to the presence of interactions. 26 For electrons in a 2DEG with effective mass m * , the static Hamiltonian reads H 0 =h 2 k 2 /2m * + V (x).…”

Section: A General Formalismmentioning

confidence: 99%

Single-parameter pumping in graphene

et al. 2011

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We propose a quantum pump mechanism based on the particular properties of graphene, namely chirality and bipolarity. The underlying physics is the excitation of evanescent modes entering a potential barrier from one lead, while those from the other lead do not reach the driving region. This induces a large nonequilibrium current with electrons stemming from a broad range of energies, in contrast to the narrow resonances that govern the corresponding effect in semiconductor heterostructures. Moreover, the pump mechanism in graphene turns out to be robust, with a simple parameter dependence, which is beneficial for applications. Numerical results from a Floquet scattering formalism are complemented with analytical solutions for small to moderate driving.

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Section: A General Formalismmentioning

confidence: 99%

Single-parameter pumping in graphene

et al. 2011

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“…Several works in this direction show indeed that ac transport in graphene is a rich subject. Studies include quantum pumping [8][9][10][11][12], nonlinear electromagnetic response [13][14][15][16][17][18], and photon-assisted tunneling phenomena [19][20][21][22][23][24][25]. In theoretical investigations for low doping (Fermi energy E F close to the Dirac point) and high frequencies , with E F and of comparable magnitude (we put = 1), a true quantum mechanical description becomes necessary.…”

Section: Introductionmentioning

confidence: 99%

Resonant second-harmonic generation in a ballistic graphene transistor with an ac-driven gate

2016

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We report a theoretical study of time-dependent transport in a ballistic graphene field effect transistor. We develop a model based on Floquet theory describing Dirac electron transmission through a harmonically driven potential barrier. Photon-assisted tunneling results in excitation of quasibound states at the barrier. Under resonance conditions, the excitation of the quasibound states leads to promotion of higher-order sidebands and, in particular, an enhanced second harmonic of the source-drain conductance. The resonances in the main transmission channel are of the Fano form, while they are of the Breit-Wigner form for sidebands. For weak ac drive strength Z 1 , the dynamic Stark shift scales as Z 4 1 , while the resonance broadens as Z 2 1 . We discuss the possibility of utilizing the resonances in prospective ballistic high-frequency devices, in particular frequency doublers operating at high frequencies and low temperatures.

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“…For the asymmetric double-well heterostructure in the presence of harmonic (dipole-like) modulations applied to both wells a heat pump was predicted which could operate at zero electron current [27]. Recently, also mono-parametric charge pumping devices have been studied both theoretically and experimentally [28][29][30][31][32][33][34][35][36][37]. Such pumps need only one external harmonic field applied to the unbiased system and thus they are of great interest.…”

Section: Introductionmentioning

confidence: 99%

“…Note that single-parameter efficient quantum pumps can be realized for different systems e.g. QDs, graphene, carbon nanotubes and nanoribbons [29][30][31][33][34][35]37]. However, periodically driving of only one system parameter (e.g.…”

Section: Introductionmentioning

confidence: 99%

Mono-parametric charge pumping through a quantum dot coupled with energy-gapped leads

Kwapiński

Taranko

2015

Eur. Phys. J. B

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Abstract. We present a proposal for a single-parametric electron pump composed of a quantum dot between two unbiased leads with energy-gapped electron density of states (DOS). The model tight-binding Hamiltonian and the evolution operator technique are used in the calculations. The quantum dot is driven by the external harmonic field which leads to the pumping current flowing from the left or right electrode depending on the system parameters. We show that the net pumping current appears in the system if (i) there are at least two sideband states: one of them lying below and the second lying above the Fermi energy; (ii) the left and right lead DOS in the vicinity of these sideband states are different. Moreover, the energy-gapped structure of DOS is visible on the average quantum dot charge and the pumped current curves as well as on the transconductance characteristics. Thus mono-parametric pumping provides useful information about the system parameters, in particular about the lead DOS structure.

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Enhancing single-parameter quantum charge pumping in carbon-based devices

Cited by 58 publications

References 43 publications

Single-parameter pumping in graphene

Single-parameter pumping in graphene

Resonant second-harmonic generation in a ballistic graphene transistor with an ac-driven gate

Mono-parametric charge pumping through a quantum dot coupled with energy-gapped leads

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