Thermal conductivity and thermal rectification of nanoporous graphene: A molecular dynamics simulation

Yousefi, Farrokh; Khoeini, Farhad; Rajabpour, Ali

doi:10.1016/j.ijheatmasstransfer.2019.118884

Cited by 62 publications

(42 citation statements)

References 39 publications

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“…This means that the heat current prefers one direction to another direction. This phenomenon occurs when the mass distribution of the system is nonsymmetric 8,16,[39][40][41] . Here, half of the system is heavier than the other half part.…”

Section: Resultsmentioning

confidence: 99%

Thermal rectification and interfacial thermal resistance in hybrid pillared-graphene and graphene: a molecular dynamics and continuum approach

2020

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In this study, we investigate the thermal rectification and thermal resistance in the hybrid pillared-graphene and graphene (PGG) system. This is done through the classical molecular dynamics simulation (MD) and also with a continuum model. At first, the thermal conductivity of both pillared-graphene and graphene is calculated employing MD simulation and Fourier's low. Our results show that the thermal conductivity of the pillared-graphene is much smaller than the graphene by an order of magnitude. Next, by applying positive and negative temperature gradients along the longitudinal direction of PGG, the thermal rectification is examined. The MD results indicate that for the lengths in the range of 36 to 86 nm, the thermal rectification remains almost constant (~3-5%). We have also studied the phonon density of states (DOS) on both sides of the interface of PGG. The DOS curves show that there is phonon scattering at low frequencies (acoustic mode) that depends on the imposed temperature gradient direction in the system. Therefore, we can 2 introduce the PGG as a promising thermal rectifier at room temperature. Furthermore, in the following of this work, we also explore the temperature distribution over the PGG by using the continuum model. The results that obtained from the continuum model predict the MD results such as the temperature distribution in the upper half-layer and lower full-layer graphene, the temperature gap and also the thermal resistance at the interface.

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Section: Resultsmentioning

confidence: 99%

Thermal rectification and interfacial thermal resistance in hybrid pillared-graphene and graphene: a molecular dynamics and continuum approach

2020

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“…The Graphene (GE), as the first isolated two-dimensional (2D) material, is composed of a honeycomb structure of carbon atoms, and have widely become popular among researchers. GE often shows different thermal 24 , 25 , mechanical 26 , 27 and optical 28 properties. However, GE has uncommon transport properties, which are related to its unusual electronic structure 29 , 30 .…”

Section: Introductionmentioning

confidence: 99%

Pure thermal spin current and perfect spin-filtering with negative differential thermoelectric resistance induced by proximity effect in graphene/silicene junctions

Gholami

Khoeini

2021

Sci Rep

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The spin-dependent Seebeck effect (SDSE) and thermal spin-filtering effect (SFE) are now considered as the essential aspects of the spin caloritronics, which can efficiently explore the relationships between the spin and heat transport in the materials. However, there is still a challenge to get a thermally-induced spin current with no thermal electron current. This paper aims to numerically investigate the spin-dependent transport properties in hybrid graphene/silicene nanoribbons (GSNRs), using the nonequilibrium Green’s function method. The effects of temperature gradient between the left and right leads, the ferromagnetic exchange field, and the local external electric fields are also included. The results showed that the spin-up and spin-down currents are produced and flow in opposite directions with almost equal magnitudes. This evidently shows that the carrier transport is dominated by the thermal spin current, whereas the thermal electron current is almost disappeared. A pure thermal spin current with the finite threshold temperatures can be obtained by modulating the temperature, and a negative differential thermoelectric resistance is obtained for the thermal electron current. A nearly zero charge thermopower is also obtained, which further demonstrates the emergence of the SDSE. The response of the hybrid system is then varied by changing the magnitudes of the ferromagnetic exchange field and local external electric fields. Thus, a nearly perfect SFE can be observed at room temperature, whereas the spin polarization efficiency is reached up to 99%. It is believed that the results obtained from this study can be useful to well understand the inspiring thermospin phenomena, and to enhance the spin caloritronics material with lower energy consumption.

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“…[ 41–44 ] In addition, more and more carbon‐based materials are being discovered for their excellent performance. [ 45–49 ] Recently, a new strategy has focused on managing phonons with nanoporous graphene (NPG) design, which aid effective heat control by engineering phonon band structures. [ 50 ] Especially, the manipulation of phonons in NPG is governed by phonon confinement and coherent interference mechanisms.…”

Section: Figurementioning

confidence: 99%

Design of Thermal Metamaterials with Excellent Thermal Control Functions by Using Functional Nanoporous Graphene

Jia

Zhang

et al. 2020

Physica Rapid Research Ltrs

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Heat flux manipulation has garnered extensive research attention due to its potential application in thermal management devices, such as heat sink, [1,2] thermal diode, [3-6] thermal transistor, [7] and thermal memory. [8] Yet until now, we were not able to control heat flux as we do with electric current. Considerable effort of researchers to investigate possible transport mechanism of microscopic particles, such as photons [9] and phonons, [10-12] has led to some significant conclusions. For instance, in 2006, Leonhardt and Pendry. [13,14] established the transformation optics theory and proposed the concept of invisible cloak, which have also been verified by subsequent experiments. Inspired by this, in 2008, Fan et al. [15] first applied the transformation theory in the field of heat transfer, and theoretically predicted the mode of thermal invisible cloak based on graded thermal metamaterial, in which the thermal conduction equation remains form invariant under coordinate transformation. However, the adverse establishing conditions of transformation thermotics theory limit the practical implementation of thermal invisible cloak. Until 2012, Narayana and Sato [16] successfully fabricated a thermal invisible cloak by constructing a concentric layered structure consisting of alternating layers of two different homogeneous isotropic thermal conductivities. Since then, a variety of thermal metamaterials, including thermal cloak and thermal concentrator, have been proposed, and some of them have been experimentally realized, [17-25] paving the way for follow-up research. It is worth noting that these novel thermal phenomena in above-mentioned metamaterials are mostly based on macroscopic compound structures such as metal/polymer. Since 2004, significant research has been directed toward two-dimensional (2D) materials. [26-31] Graphene, as a representative 2D material, is considered as a promising candidate for next-generation electronic and optoelectronic devices due to its exceptional charge carrier mobility and 2D nature. [32-36] In addition, ultrahigh phonon-dominated thermal conductivity of graphene facilitates its use as heat sinks in integrated circuits. [1,2,37] Moreover, the fast response speed in graphene induced by large phonon group velocity can be applied in thermal devices performed with phonons. For example, Wang et al. studied the thermal rectification (TR) effect in asymmetrically defected graphene nanoribbon (GNR) and showed that singlevacancies and Si defects are more preferable in thermal rectifier fabrication. [38] A similar result has been obtained by experimental studies on asymmetrically defected GNR. [39] Furthermore, Pal and Puri realized the function of thermal logic gate based on two asymmetric graphene thermal diodes.

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Thermal conductivity and thermal rectification of nanoporous graphene: A molecular dynamics simulation

Cited by 62 publications

References 39 publications

Thermal rectification and interfacial thermal resistance in hybrid pillared-graphene and graphene: a molecular dynamics and continuum approach

Thermal rectification and interfacial thermal resistance in hybrid pillared-graphene and graphene: a molecular dynamics and continuum approach

Pure thermal spin current and perfect spin-filtering with negative differential thermoelectric resistance induced by proximity effect in graphene/silicene junctions

Design of Thermal Metamaterials with Excellent Thermal Control Functions by Using Functional Nanoporous Graphene

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