Directly visualizing the crossover from incoherent to coherent phonons in two-dimensional periodic MoS2/MoSe2 arrayed heterostructure

An, Meng; Chen, Dongsheng; Ma, Weigang; Hu, Shiqian; Zhang, Xing

doi:10.1016/j.ijheatmasstransfer.2021.121630

Cited by 19 publications

(8 citation statements)

References 49 publications

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“…The spectral thermal conductivity [25,46] is calculated by setting up an imaginary interface to calculate the heat flow of an arbitrary atom, as shown in the following equation:…”

Section: Numerical Simulation Details and Calculation Methodsmentioning

confidence: 99%

“…In addition, Sääskilahti et al [24] proposed a phenomenological expression for phonon transport that encompasses all relevant transport mechanisms, explaining the interaction between phonon coherent wave interference and incoherent phonon transport in non-periodic superlattices. An et al [25] confirmed the localization of phonon thermal transport due to multiple scattering and interference of wide bandgap phonons caused by the random distribution of ErAs nanodots at the interface of GaAs/AlAs superlattice by measuring the TC [26]. Compared to experiments, atomic simulations can more readily create conditions for observing coherent phonon transport and phonon localization phenomena, such as the establishment of highly disordered and cryogenic systems.…”

Section: Introductionmentioning

confidence: 99%

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Thermal transport and phonon localization in periodic h-GaN/h-AlN superlattices

Chen,

Wang

2023

J. Phys.: Condens. Matter

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The widely observed non-diffusive phonon thermal transport phenomenon in nanostructures is largely attributed to classical size effects, which ignore the characteristic of phonon wave. In this context, the crossover transition process from incoherent to coherent phonon transport in two-dimensional heterogeneous periodic h-GaN/h-AlN superlattices is demonstrated using a non-equilibrium molecular dynamics approach, where the localization behavior of thermal phonons is particularly significant. The results show that the thermal transport of the superlattice structure is affected by a combination of structural parameters and temperature. The thermal conductivity (TC) of the superlattice decreases and then increases as the interface density increases. Phonon-interface scattering dominates the incoherent phonon transport, while local phonons modulate the transport in the coherent region. Thus, the competition between phonon wave and particle properties causes the transition from incoherent to coherent phonon transport. In addition, as the TC valley depth slows down with increasing system temperature, the scattering of medium and high frequency phonons is enhanced and the phonon lifetime decreases. Research on localized phonons in superlattices provides theoretical support for thermal transport regulation in basal low-dimensional materials.

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“…The spectral thermal conductivity [25,46] is calculated by setting up an imaginary interface to calculate the heat flow of an arbitrary atom, as shown in the following equation:…”

Section: Numerical Simulation Details and Calculation Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Thermal transport and phonon localization in periodic h-GaN/h-AlN superlattices

Chen,

Wang

2023

J. Phys.: Condens. Matter

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“…The measured thermal conductivities (λ) of homogeneous MoSe 2 (sample 5) and WSe 2 (sample 6) are 45 and 40 W/(m⋅K) at room temperature, which is consistent with the literature values ( 25 , 26 ), proving the measurement accuracy of the H-type method. The flattened tendency of the thermal conductivity versus temperature curve was attributed to the atomic doping and SiO 2 substrate–induced phonon scattering, which is ubiquitous in monolayer 2D materials ( 27 , 28 ). The λ discrepancies of homogeneous MoSe 2 and WSe 2 in different heat flow directions are <3%, showing no TR effect, as expected.…”

Section: Thermal Rectification Measurementmentioning

confidence: 99%

Simultaneous electrical and thermal rectification in a monolayer lateral heterojunction

Zhang

Wang

et al. 2022

Science

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Efficient waste heat dissipation has become increasingly challenging as transistor size has decreased to nanometers. As governed by universal Umklapp phonon scattering, the thermal conductivity of semiconductors decreases at higher temperatures and causes heat transfer deterioration under high-power conditions. In this study, we realized simultaneous electrical and thermal rectification (TR) in a monolayer MoSe 2 -WSe 2 lateral heterostructure. The atomically thin MoSe 2 -WSe 2 heterojunction forms an electrical diode with a high ON/OFF ratio up to 10 4 . Meanwhile, a preferred heat dissipation channel was formed from MoSe 2 to WSe 2 in the ON state of the heterojunction diode at high bias voltage with a TR factor as high as 96%. Higher thermal conductivity was achieved at higher temperatures owing to the TR effect caused by the local temperature gradient. Furthermore, the TR factor could be regulated from maximum to zero by rotating the angle of the monolayer heterojunction interface. This result opens a path for designing novel nanoelectronic devices with enhanced thermal dissipation.

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“…From the theoretical point of view, the most common approaches for the LTC rely on the Boltzmann transport equation, 47 via ab initio calculations, [48][49][50][51] Green's functions, [52][53][54][55] and molecular dynamics (MD) simulations. [56][57][58][59][60][61][62][63][64] Despite the success of these methods, they are computationally expensive, which poses limitations for extensive LTC analyses of 2D nanomaterials aimed to potential applications. Therefore, faster and simpler ways to estimate LTC for 2D nanomaterials are of great importance.…”

Section: Introductionmentioning

confidence: 99%