Geometry Effects on the Phonon-Drag Contribution to Thermopower in a Coupled-Quantum-Well System at Low Temperature

Vazifehshenas, T.; Rahnama, S.; Salavati-fard, Taha

doi:10.1007/s10909-015-1334-6

Cited by 4 publications

(4 citation statements)

References 47 publications

(42 reference statements)

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“…By substituting the temperature-dependent screening function [15] into the phonon-drag induced Seebeck coefficient of BLG [7] and using results from our previous work [12], we scrutinize the screening effect on S g in the BLG-q2DEG double layer system.and obtain some results: For the double layer system, we point out the incorrectness of a previous screening function used in Refs. [9,10]. Thus we use a more exact screening function derived recently by many authors [6,23,26,27] using the Feynman diagram techniques for two-component systems.…”

Section: Discussionmentioning

confidence: 99%

“…Later, Ansari and Ashraf [8] investigated the screening effect on S g in BLG with the = T K 0 screening function. For the double layer systems, Smith et al [9] and Vazifehshenas and Rahnama [10] studied the Seebeck coefficient S g in q2DEG-q2DEG structures with screening effect taken into account. However, we find that the double layer screening functions used by these authors are incorrect.…”

Section: Introductionmentioning

confidence: 99%

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Screening effect on the phonon drag induced seebeck coefficient in bilayer graphene/quasi-two-dimensional electron gas structures

Van Tuan,

Khanh,

Van Tai

et al. 2024

Phys. Scr.

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In this work, we investigate the impacts of the temperature-dependent screening effect on the Seebeck coefficient originating from the phonon drag, namely phonon—drag thermopower S g , of a double layer system consisting of bilayer graphene (BLG) separated from a quasi-two-dimensional electron gas (q2DEG) by an air medium (hereafter referred to as BLG-q2DEG). For such a system, we can assume that the two-dimensional (2D) electrons in BLG only interact internally with acoustic phonons. We consider the effects of screening induced by the 2D electrons in q2DEG on the electron–phonon interactions in BLG by comparing with the results obtained when only using the monolayer screening function in BLG. The monolayer screening functions in BLG (q2DEG) do not depend on the distance d between the two layers, and the screening function of the double layer system approaches the respective monolayer screening functions for large d. When taking into account of the screening effect caused by charged carriers in both layers, S g of a BLG-q2DEG decreases compared to the case of only considering the monolayer screening effect, especially in the low-T regime. With different carrier densities in the two layers N s BLG ≠ N s GaAs , it has shown that S g strongly depends on BLG. Besides, when changing the width L of the q2DEG such as GaAs quantum well, the double layer screening function makes S g increase for small L and negligibly affects S g for large L. On the contrary, the monolayer screening functions make S g decrease for large L. The monolayer screening functions cause S g to increase for N s BLG < N s GaAs .

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Screening effect on the phonon drag induced seebeck coefficient in bilayer graphene/quasi-two-dimensional electron gas structures

Van Tuan,

Khanh,

Van Tai

et al. 2024

Phys. Scr.

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“…In the last two decades, many theoretically and experimentally works are done on the quasi-particles inelastic scattering rate of 2DEG such as geometry effect [31,35], local field correction effect in finite temperature [33], Hubbard correction infinite temperature [36,40] and, Coulomb scattering lifetime [30]. Also, interesting researches are done on this parameter of DQW such as electron-electron scattering [7], Coulomb scattering lifetime [24], Coulomb drag [6,13,14,21] and geometry effect in finite temperature [17,22,41]. The dynamical dielectric function is the most important parameter for calculation of quasi-particles inelastic scattering rate.…”

Section: Introductionmentioning

confidence: 99%

Local field correction effects on quasi-particle inelastic scattering rate in a coupled-quantum-layers system at finite temperature

Rafee¹,

Razeghizadeh²,

Gharaati³

2018

Indian J Phys

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Local field correction effects on intra-layer inelastic scattering rate of interacting electrons are theoretically investigated in a coupled-quantum-wells structure, at finite temperature. At first, temperature dependent dynamic dielectric function is calculated using random phase approximation (RPA). Then, local field correction effects are considered in calculations by employing short-range effects of exchange-correlation holes around electrons. We employ Hubbard, finite-temperature Hubbard and STLS approximations. Finally, quasi-particle inelastic scattering rate is calculated using the imaginary part of the electron self-energy within GW method. The results show that quasi-particle inelastic scattering rate is reduced, when a local field correction is employed, at any temperature, wave vector and electron density.

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“…Cấu tạo lớp đôi BLG-BLG với các nền điện môi khác nhau.Hệ số Seebeck phonon drag của hệ ghép đôi có dạng9,10 ,S g = σ u S g u + σ l S g l σ u + σ l (6)trong đó σ là độ dẫn điện, σ = N s e 2 τ t (E k )/m * ; u, l ứng với lớp trên và lớp dưới. Nghiên cứu trong bài báo này được giới hạn ở mô hình BLG-BLG đặt trong không khí với κ 1 = κ 2 = κ 3 = 1.…”

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Study the effects on the phonon drag Seebeck coefficient of bilayer graphene and bilayer graphene−bilayer graphene double layers

Van Tuan,

Quoc Khanh

2023

Sci. Tech. Dev. J. - Nat. Sci.

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This paper presented the investigation of the influence of the temperature−dependent screening effect on the Seebeck phonon drag coefficient Sg of a monolayer of bilayer graphene (BLG) and a BLG−BLG double layer placed in an air environment. For a system in an air environment, the two-dimensional electrons of the BLG was assumed to interact only with the intralayer deformation acoustic potential phonons in the BLG. After reviewing the results published by Kubakaddi and Bhargavi, “Enhancement of phonon-drag thermopower in bilayer graphene” in Phys. Rev. B 82, 155410 (2010), this paper expanded the mentioned-results to encompass the screening and double layers and found that the phonon drag coefficient in the BLG monolayer system was strongly reduced by the screening effect, even up to several orders of magnitude compared to the zero temperature screening function, as shown in some recent publications. When comparing the effect of electron screening in the second layer on electron-phonon interaction in the remaining layer, or on the intralayer screening function, the distance between the two layers was small. The screening effect of the second layer significantly reduced the magnitude of the phonon drag Seebeck coefficient Sg in the BLG-BLG double layer. The effect of temperature, layer spacing and particle density on Sg for symmetric and asymmetric systems with varying layer densities were also investigated.

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Geometry Effects on the Phonon-Drag Contribution to Thermopower in a Coupled-Quantum-Well System at Low Temperature

Cited by 4 publications

References 47 publications

Screening effect on the phonon drag induced seebeck coefficient in bilayer graphene/quasi-two-dimensional electron gas structures

Screening effect on the phonon drag induced seebeck coefficient in bilayer graphene/quasi-two-dimensional electron gas structures

Local field correction effects on quasi-particle inelastic scattering rate in a coupled-quantum-layers system at finite temperature

Study the effects on the phonon drag Seebeck coefficient of bilayer graphene and bilayer graphene−bilayer graphene double layers

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