TETHYS: A simulation tool for graphene hydrodynamic models

Cosme, Pedro; Santos, João S.; Bizarro, João P. S.; Figueiredo, Ivan

doi:10.1016/j.cpc.2022.108550

Cited by 5 publications

(4 citation statements)

References 28 publications

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“…From such a looped transmission line, we show that the growth rate of the unstable modes is enhanced. Alongside this, fully nonlinear simulations performed by tethys simulation tool [15] evince these findings from a numerical approach while also proving the enhancement of the saturation amplitude.…”

Section: Introductionmentioning

confidence: 54%

“…On the contrary, closing the feedback loop leads to a significant increase in the saturation amplitude and to a faster saturation itself. However, the waveform is distorted into a new shape due to the interplay of the higher order modes in the expansion of equation (15). More importantly, it is clear from the simulations presented in figure 4 that the growth rate is much higher, not only the saturation is attained much faster, but the amplitude envelope of the waveforms is steeper near…”

Section: Nonlinear Simulationsmentioning

confidence: 91%

“…To surpass the limitations of the linear analysis, the hydrodynamic system of equation ( 1) needs to be numerically simulated so that the full nonlinear effects could manifest. We resorted to Tethys computer program [15], a finite-volume solver designed for the simulation of graphene electrohydrodynamics.…”

Section: Nonlinear Simulationsmentioning

confidence: 99%

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Feedback enhanced Dyakonov–Shur instability in graphene field-effect transistors

Cosme,

Simões

2024

J. Phys.: Condens. Matter

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Graphene devices are known to have the potential to operate THz signals. In particular,graphene field-effect transistors have been proposed as devices to host plasmonic instabilities in the THz realm; for instance, Dyakonov-Shur instability which relies upondc excitation. %In this work, starting from a hydrodynamical description of the charge carriers, we extend the transmission line description of graphene field-effect transistors to a scheme with a positive feedback loop, also considering the effects of delay, which leads to the transcendental transfer function with terms of the form $e^{a s}\sech^k(s)/s$.Applying the conditions for the excitation of Dyakonov--Shur instability, we report an enhanced voltage gain in the linear regime that is corroborated by our simulations of the nonlinear hydrodynamic model for the charge carriers. This translates to both greater saturation amplitude -- often up to 50\% increase -- and faster growth rate of the self-oscillations. Thus, we bring forth a prospective concept for the realization of a THz oscillator suitable for future plasmonic circuitry.

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Section: Introductionmentioning

confidence: 54%

Section: Nonlinear Simulationsmentioning

confidence: 91%

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Feedback enhanced Dyakonov–Shur instability in graphene field-effect transistors

Cosme,

Simões

2024

J. Phys.: Condens. Matter

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“…The fluid dynamics model for plasmonic is a kind of macro approach to a micro problems [1][2][3][4]. It combines the Maxwell equation, Euler fluid dynamics equation, and continuity equation, with a supplementary term caused by the statistical pressure of the electron gas [5,6].…”

Section: Introductionmentioning

confidence: 99%

Energy Losses by the Interaction of Charged Particles with a Graphene Sheet

Wang

Sun

Hua

et al. 2023

AJOPACS

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Using the fluid dynamics model, we studied the formation of graphene surface plasma when the charge is tilted to the graphene sheet for motion. We calculated the electron energy loss spectrum of electrons at different angles and proved that the resonance in the spectrum is related to the frequency of graphene surface plasma, as the electron velocity decreases, the dispersion shifts to higher energies. An increase in the tilt angle will also shift the dispersion energy in a higher range.

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Nonlinear density waves on graphene electron fluids

Cosme¹,

Terças²

2023

Phys. Rev. B

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TETHYS: A simulation tool for graphene hydrodynamic models

Cited by 5 publications

References 28 publications

Feedback enhanced Dyakonov–Shur instability in graphene field-effect transistors

Feedback enhanced Dyakonov–Shur instability in graphene field-effect transistors

Energy Losses by the Interaction of Charged Particles with a Graphene Sheet

Nonlinear density waves on graphene electron fluids

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