Scattering approach to frequency-dependent current noise in Fabry-Pérot graphene devices

Hammer, Jan; Belzig, Wolfgang

doi:10.1103/physrevb.87.125422

Cited by 8 publications

(6 citation statements)

References 85 publications

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“…Another notable feature is the oscillations of both the conductance and the Fano factor on the scale of 1/L. These oscillations are associated with Fabry-Pérot resonances 58 induced by two partly reflecting mirrors at the interfaces between the channel and the contacts [at x = −L 1 and x = L 2 in Fig. 1(b)].…”

Section: A DC Characteristicsmentioning

confidence: 98%

“…Several theoretical studies of shot noise in graphene have also appeared recently. Signatures of Fabry-Pérot interferences in the shot noise have been investigated, both the zero frequency noise 41 and the finite frequency noise 58 . In the latter case, it was shown that the noise power oscillates with frequency on a scale set by the Fabry-Pérot energy scale L/ v F , where v F is the Fermi velocity and L is the distance between source and drain contacts.…”

Section: Introductionmentioning

confidence: 99%

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Shot noise in a harmonically driven ballistic graphene transistor

2017

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We study time-dependent electron transport and quantum noise in a ballistic graphene field effect transistor driven by an ac gate potential. The non-linear response to the ac signal is computed through Floquet theory for scattering states and Landauer-Büttiker theory for charge current and its fluctuations. Photon-assisted excitation of a quasibound state in the top-gate barrier leads to resonances in transmission that strongly influence the noise properties. For strong doping of graphene under source and drain contacts, when electrons are transmitted through the channel via evanescent waves, the resonance leads to a substantial suppression of noise. The Fano factor is then reduced well below the pseudo-diffusive value, F < 1/3, also for strong ac drive. The good signal-to-noise ratio (small Fano factor) on resonance suggests that the device is a good candidate for high-frequency (THz) radiation detection. We show analytically that Klein tunneling (total suppression of back-reflection) persists for perpendicular incidence also when the barrier is driven harmonically. Although the transmission is inelastic and distributed among sideband energies, a sum rule leads to total suppression of shot noise.

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Section: A DC Characteristicsmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Shot noise in a harmonically driven ballistic graphene transistor

2017

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“…More subtle coherence effects can also be detected through noise measurements in Andreev interferometers [15,16]. Furthermore, noise has for example been used to characterize entanglement via the violation of Bell-type inequalities [17,18,19], to probe many-body states of ultracold atoms [20], to reveal the relativistic quantum dynamics in graphene [21,22], to observe Majorana bound states in p-wave superconductors [23] and in many more applications.…”

Section: Introductionmentioning

confidence: 99%

Non-classical current noise and light emission of an ac-driven tunnel junction

2020

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The non-symmetrized current noise is crucial for the analysis of light emission in nanojunctions. The latter represent non-classical photon emitters whose description requires a full quantum approach. It was found experimentally that light emission can occur with a photon energy exceeding the applied dc voltage, which intuitively should be forbidden due to the Pauli principle. This overbias light emission cannot be described by the single-electron physics, but can be explained by two-electron or even three-electron processes, correlated by a local resonant mode in analogy to the well-known dynamical Coulomb blockade (DCB). Here, we obtain the non-symmetrized noise for junctions driven by an arbitrarily shaped periodic voltage. We find that when the junction is driven, the overbias light emission exhibits intriguingly different features compared to the dc case. In addition to kinks at multiples of the bias voltage, side kinks appear at integer multiples of the ac driving frequency. Our work generalizes the DCB theory of light emission to driven tunnel junctions and opens the avenue for engineered quantum light sources, which can be tuned purely by applied voltages.

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“…The most dramatic effects of light-matter interation are manifested in a suppression of the conductance. In contrast to a time-periodic external light field, time-dependent modulation of gate or contact potentials and the accompanied photo-assisted tunneling of electrons lead to a great variety of interesting phenomena [38][39][40][41][42][43] .…”

Section: Introductionmentioning

confidence: 99%

Transport through vertical graphene contacts under intense laser fields

Stadler,

Löfwander,

Fogelström

2020

Preprint

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We theoretically study the electronic and transport properties of two graphene layers vertically coupled by an insulating layer under the influence of a time-periodic external light field. The nonadiabatic driving induces excitations of electrons and a redistribution of the occupied states which is manifested in the opening of gaps in the quasienergy spectrum of graphene. When a voltage is applied between the top and bottom graphene layers, the photo-induced nonequilibrium occupation modifies the transport properties of the contact. We investigate the electronic and transport properties of the contact by using the nonequilibrium Green's function formalism. To illustrate the behavior of the differential conductance of the vertical contact under the light illumination, we consider two cases. First, we assume that both the bottom and top layers consist of graphene and second we consider a finite mass term in the bottom layer. We obtain that the differential conductance is strongly suppressed due to the opening of gaps in the quasienergy spectrum in graphene. Additionally, the conductance shows features corresponding to the tunneling of photoexcited electrons at energies of the van Hove singularity for both the top and bottom layers. In the case of a finite mass term in the bottom layer, the differential conductance can be directly related to the tunneling of photoexcited electrons.

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Scattering approach to frequency-dependent current noise in Fabry-Pérot graphene devices

Cited by 8 publications

References 85 publications

Shot noise in a harmonically driven ballistic graphene transistor

Shot noise in a harmonically driven ballistic graphene transistor

Non-classical current noise and light emission of an ac-driven tunnel junction

Transport through vertical graphene contacts under intense laser fields

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