Thermal transport across grain boundaries in polycrystalline silicene: A multiscale modeling

Khalkhali, Maryam; Rajabpour, Ali; Khoeini, Farhad

doi:10.1038/s41598-019-42187-w

Cited by 28 publications

(19 citation statements)

References 66 publications

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“…A similar trend for temperature drop in the vicinity of grain boundaries, having mentioned pentagon-heptagon defect pairs, was reported for polycrystalline silicene by Khalkhali et al . 40 .…”

Section: Resultsmentioning

confidence: 99%

An insight into thermal properties of BC3-graphene hetero-nanosheets: a molecular dynamics study

Dehaghani

Molaei

Yousefi

et al. 2021

Sci Rep

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Simulation of thermal properties of graphene hetero-nanosheets is a key step in understanding their performance in nano-electronics where thermal loads and shocks are highly likely. Herein we combine graphene and boron-carbide nanosheets (BC3N) heterogeneous structures to obtain BC3N-graphene hetero-nanosheet (BC3GrHs) as a model semiconductor with tunable properties. Poor thermal properties of such heterostructures would curb their long-term practice. BC3GrHs may be imperfect with grain boundaries comprising non-hexagonal rings, heptagons, and pentagons as topological defects. Therefore, a realistic picture of the thermal properties of BC3GrHs necessitates consideration of grain boundaries of heptagon-pentagon defect pairs. Herein thermal properties of BC3GrHs with various defects were evaluated applying molecular dynamic (MD) simulation. First, temperature profiles along BC3GrHs interface with symmetric and asymmetric pentagon-heptagon pairs at 300 K, ΔT = 40 K, and zero strain were compared. Next, the effect of temperature, strain, and temperature gradient (ΔT) on Kaptiza resistance (interfacial thermal resistance at the grain boundary) was visualized. It was found that Kapitza resistance increases upon an increase of defect density in the grain boundary. Besides, among symmetric grain boundaries, 5–7–6–6 and 5–7–5–7 defect pairs showed the lowest (2 × 10–10 m2 K W−1) and highest (4.9 × 10–10 m2 K W−1) values of Kapitza resistance, respectively. Regarding parameters affecting Kapitza resistance, increased temperature and strain caused the rise and drop in Kaptiza thermal resistance, respectively. However, lengthier nanosheets had lower Kapitza thermal resistance. Moreover, changes in temperature gradient had a negligible effect on the Kapitza resistance.

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Section: Resultsmentioning

confidence: 99%

An insight into thermal properties of BC3-graphene hetero-nanosheets: a molecular dynamics study

Dehaghani

Molaei

Yousefi

et al. 2021

Sci Rep

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“…There is still some way to use awesome graphene properties in various situation. Graphene properties such as electronic, thermal, and optical show strongly tunable with impurity doping [12], defects [13], and mechanical straining [14]. Alongside these tuning methods, the lithography technique is applicable on graphene sheet to produce a various configuration that introduced recently [15].…”

Section: Introductionmentioning

confidence: 99%

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

Yousefi

Khoeini

Rajabpour

2020

International Journal of Heat and Mass Transfer

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Using non-equilibrium molecular dynamics (NEMD) simulation, we study thermal properties of the so-called nanoporous graphene (NPG) sheet which contains a series of nanoporous in an ordered way and was synthesized recently (Science 360 (2018), 199).The dependence of thermal conductivity on sample size, edge chirality, and porosity concentration are investigated. Our results indicate that the thermal conductivity of NPG is about two orders smaller compared with of pristine graphene. Therefore this sheet can be used as a thermoelectric material. Also, the porosity concentration helps us to tune the thermal conductivity. Moreover, the results show that the thermal conductivity increases with growing sample length due to ballistic transport. On the other hand, along the armchair direction, the thermal conductivity is larger than zigzag direction. We also examined the thermal properties of the interface of NPG and graphene. The temperature drops significantly through the interface leading to the thermal resistance. The thermal resistance changes with imposed heat flux direction, and this difference cause significantly large thermal rectification factor, and heat current prefers one direction to another. Besides, to investigate those quantities fundamentally, we study the phonon density of states and scattering of them.2

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“…There is also the interaction between the electromagnetic field and spin-orbit coupling in the SE, a feature that can be used to study physics in quantum phase transition 42 . More recently, several studies have been carried out by researchers to investigate the charge and spin thermal transport properties of the SE [43][44][45] .…”

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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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Thermal transport across grain boundaries in polycrystalline silicene: A multiscale modeling

Cited by 28 publications

References 66 publications

An insight into thermal properties of BC3-graphene hetero-nanosheets: a molecular dynamics study

An insight into thermal properties of BC3-graphene hetero-nanosheets: a molecular dynamics study

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

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

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