Efficient quantum modeling of inelastic interactions in nanodevices

Lee, Y.; Lannoo, M.; Cavassilas, Nicolas; Luisier, Mathieu; Bescond, Marc

doi:10.1103/physrevb.93.205411

Cited by 20 publications

(24 citation statements)

References 37 publications

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“…However, it was also shown that the spectral currents built by the 1st LOA Green's function are very far from the SCBA results since only the first order in the interaction was included. In References [31,32], it was shown that, by using the term ∆g 1 = g 0 Σ[g 0 ]g 0 from Equation (6) as a basic building block, the generalized LOA expansion series can be built as…”

Section: Lowest Order Approximationmentioning

confidence: 99%

“…The overall schematic of practical calculations for the LOA Green's function g N , which was explained in Reference [32] in detail, is summarized in Algorithm 1 below.…”

Section: Lowest Order Approximationmentioning

confidence: 99%

“…In this article, we review a highly efficient method [30][31][32][33][34], the so-called lowest order approximation (LOA) analytically continued by Padé approximants, to treat inelastic interactions within the NEGF framework. The main idea behind the method is to collect only the low-order scattering diagrams that guarantee the conservation of the current.…”

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confidence: 99%

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Quantum Treatment of Inelastic Interactions for the Modeling of Nanowire Field-Effect Transistors

et al. 2019

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During the last decades, the Nonequilibrium Green's function (NEGF) formalism has been proposed to develop nano-scaled device-simulation tools since it is especially convenient to deal with open device systems on a quantum-mechanical base and allows the treatment of inelastic scattering. In particular, it is able to account for inelastic effects on the electronic and thermal current, originating from the interactions of electron-phonon and phonon-phonon, respectively. However, the treatment of inelastic mechanisms within the NEGF framework usually relies on a numerically expensive scheme, implementing the self-consistent Born approximation (SCBA). In this article, we review an alternative approach, the so-called Lowest Order Approximation (LOA), which is realized by a rescaling technique and coupled with Padé approximants, to efficiently model inelastic scattering in nanostructures. Its main advantage is to provide a numerically efficient and physically meaningful quantum treatment of scattering processes. This approach is successfully applied to the three-dimensional (3D) atomistic quantum transport OMEN code to study the impact of electron-phonon and anharmonic phonon-phonon scattering in nanowire field-effect transistors. A reduction of the computational time by about ×6 for the electronic current and ×2 for the thermal current calculation is obtained. We also review the possibility to apply the first-order Richardson extrapolation to the Padé N/N − 1 sequence in order to accelerate the convergence of divergent LOA series. More in general, the reviewed approach shows the potentiality to significantly and systematically lighten the computational burden associated to the atomistic quantum simulations of dissipative transport in realistic 3D systems.

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Section: Lowest Order Approximationmentioning

confidence: 99%

“…The overall schematic of practical calculations for the LOA Green's function g N , which was explained in Reference [32] in detail, is summarized in Algorithm 1 below.…”

Section: Lowest Order Approximationmentioning

confidence: 99%

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Quantum Treatment of Inelastic Interactions for the Modeling of Nanowire Field-Effect Transistors

et al. 2019

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“…Therefore, calculations of the scattering self-energies and the interacting Green's functions usually rely on a self-consistent scheme called the "self-consistent Born approximation" (SCBA). Alternative direct (i.e., not self-consistent) techniques [12][13][14][15] have been recently developed to calculate the scattering self-energies, but for the sake of clarity, they will not be addressed in this special issue.…”

Section: Introductionmentioning

confidence: 99%

Introduction

Bescond

Dollfus

2016

J Comput Electron

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The continuous downscaling of electronic devices has led to remarkable broadening of applications during the last twenty years, from nanoelectronics through the photovoltaics and more recently quantum computing.Although these devices have reached nanodimensions, with carrier transport approaching the ballistic limit in the active region, it is widely recognized that inelastic scattering have still a significant influence. For instance, it has been shown theoretically that electron-phonon scattering drastically influences the current characteristics in ultimate nanowire transistors [1]. The miniaturization tends to enhance also the impact of thermal effects, and accurate description of phonon scattering at the nanoscale is becoming crucial to understand and manage thermal dissipation in devices and circuits [2]. In modern optoelectronic devices like new generation solar cells, it is also essential to consider appropriate models of light-matter interaction at the microscopic level [3,4]. Time-dependent quantum transport models are becoming more and more relevant to correctly assess and predict the properties of electronic quantum computing devices. In such devices, the energy of an electron can change during its travel across the active region and timedependent modeling techniques are essential to predict their physical behavior [5]. B Philippe Dollfus

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“…Reducing the computational cost of inelastic, compared to elastic, device simulations has therefore been an important and unsolved challenge for decades since the first ultrascaled transistors emerged. In the extreme limit of molecular-scale devices there are accurate first-principles methods for inelastic processes available [2][3][4][5][6][7][8][9][10][11][12][13], while in the opposite bulk continuum limit, deformation potentials (DPs) are extracted for Boltzmann transport equations (BTEs) that accurately describe low bias transport [14][15][16][17]. However, in between these two regimes efficient computational methods are missing.…”

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confidence: 99%

First-principles electron transport with phonon coupling: Large scale at low cost

et al. 2017

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Phonon-assisted tunneling plays a crucial role for electronic device performance and even more so with future size down-scaling. We show how one can include this effect in large-scale first-principles calculations using a single "special thermal displacement" (STD) of the atomic coordinates at almost the same cost as elastic transport calculations, by extending the recent method of Zacharias et al. [Phys Rev. B 94, 075125 (2016)] to the important case of Landauer conductance. We apply the method to ultra-scaled silicon devices and demonstrate the importance of phonon-assisted band-toband and source-to-drain tunneling. In a diode the phonons lead to a rectification ratio suppression in good agreement with experiments, while in an ultra-thin body transistor the phonons increase offcurrents by four orders of magnitude, and the subthreshold swing by a factor of four, in agreement with perturbation theory.

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Efficient quantum modeling of inelastic interactions in nanodevices

Cited by 20 publications

References 37 publications

Quantum Treatment of Inelastic Interactions for the Modeling of Nanowire Field-Effect Transistors

Quantum Treatment of Inelastic Interactions for the Modeling of Nanowire Field-Effect Transistors

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First-principles electron transport with phonon coupling: Large scale at low cost

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