Nonequilibrium phonon mean free paths in anharmonic chains

Sääskilahti, Kimmo; Oksanen, Jani; Volz, Sébastian; Tulkki, Jukka

doi:10.1103/physrevb.92.245411

Cited by 35 publications

(63 citation statements)

References 44 publications

(85 reference statements)

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“…The nonequilibrium heat current can be further decomposed for different frequencies, as recently demonstrated by Sääskilahti et al [31,32]. Here, we extend their method to include the in-out decomposition.…”

Section: Spectral Decompositionmentioning

confidence: 97%

“…First, the system can either have fixed [32,[42][43][44] or periodic boundary conditions [9,23,24,36,39] along the transport direction. Second, the nonequilibrium heat current can be generated by different methods, including the velocity rescaling method by Jund and Jullien [24], the velocity-swapping method by Müller-Plathe [23], or the thermostat method [6,32,[42][43][44]. It has been found that the results do not sensitively depend on the methods chosen (see, e.g., [9]).…”

Section: B Nonequilibrium Molecular Dynamics Methodsmentioning

confidence: 99%

“…Before presenting the NEMD results for the samples with different lengths, we first note that the nonequilibrium heat current components can be further spectrally decomposed [32]. The correlation function K in/out A→B (t) and the spectral heat current q in/out A→B (ω) in a quasiballistic (20 nm long excluding the heat source and sink) sample, with or without strain, is shown in Fig.…”

Section: Fig 3 (A)mentioning

confidence: 99%

“…In Sec. II C, the spectral decomposition method of Sääskilahti et al [31,32] is generalized to include the in-out decomposition. Some details of our MD simulations are then presented in Sec.…”

Section: Introductionmentioning

confidence: 99%

“…However, when used in their traditional form, little insight can be gained regarding the underlying transport * brucenju@gmail.com mechanisms. There have been intensive efforts in developing MD-based methods for studying spectrally decomposed properties [25][26][27][28][29][30][31][32][33][34][35], but most of them are targeted for general materials. One exception is the method by Gill-Comeau and Lewis [34], where the total thermal conductivity is decomposed into a single-particle component and a collective one, the latter being crucial to materials in which the nonresistive normal (non-umklapp) scattering is important, which is the case for graphene [10,14,15].…”

Section: Introductionmentioning

confidence: 99%

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Thermal conductivity decomposition in two-dimensional materials: Application to graphene

et al. 2017

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Two-dimensional materials have unusual phonon spectra due to the presence of flexural (out-of-plane) modes. Although molecular dynamics simulations have been extensively used to study heat transport in such materials, conventional formalisms treat the phonon dynamics isotropically. Here, we decompose the microscopic heat current in atomistic simulations into in-plane and out-of-plane components, corresponding to in-plane and outof-plane phonon dynamics, respectively. This decomposition allows for direct computation of the corresponding thermal conductivity components in two-dimensional materials. We apply this decomposition to study heat transport in suspended graphene, using both equilibrium and nonequilibrium molecular dynamics simulations. We show that the flexural component is responsible for about two-thirds of the total thermal conductivity in unstrained graphene, and the acoustic flexural component is responsible for the logarithmic divergence of the conductivity when a sufficiently large tensile strain is applied.

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Section: Spectral Decompositionmentioning

confidence: 97%

Section: B Nonequilibrium Molecular Dynamics Methodsmentioning

confidence: 99%

Section: Fig 3 (A)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal conductivity decomposition in two-dimensional materials: Application to graphene

et al. 2017

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Remarkable Reduction of Interfacial Thermal Resistance in Nanophononic Heterostructures

Ren

Liu

Chen

et al. 2020

Adv Funct Materials

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This work investigates interfacial thermal transport in phononic-mismatched heterostructures that consists of pristine black phosphorene and its phononic crystal. It is found that the presence of the sub-periodic structure results in reduced thermal conductivity in phononic crystals. As opposed to intuitive expectations, a slight temperature jump is observed at the interface of nanophononic heterostructures, which is only about 10% of that at conventional interfaces consisting of dissimilar materials. Consequently, contact thermal conductance in the nanophononic heterostructure is 10−30 times higher than that of mass-mismatched interfaces in a comparative study. Moreover, in contrast to conventional heterostructures achieved by interfacing dissimilar materials, weak temperature dependence is observed in interfacial thermal conductance, and thermal rectification is sharply suppressed. These phenomena are well explained based on lattice dynamic insights. This work not only enhances the understanding of the fundamental physics of phonons transport across interface, but also facilitates the possible spectrum of application ranges from thermoelectrics, thermal management, to thermal cloak.

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Moiré Pattern Controlled Phonon Polarizer Based on Twisted Graphene

Qin,

Dai,

et al. 2024

Advanced Materials

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Atomically twisted van der Waals materials featuring Moiré patterns present new design possibilities and demonstrate unconventional behaviors in electrical, optical, spintronic, and superconducting properties. However, experimental exploration of thermal transport across Moiré patterns has not been as extensive, despite its critical role in nanoelectronics, thermal management, and energy conversion. Here, we conduct the first experimental investigation into thermal transport across twisted graphene, demonstrating the concept of a phonon polarizer achieved by manipulating the rotational misalignment between adjacent stacked layers. Our approach includes thorough structural characterizations and atomistic modeling of various twisted graphene configurations, along with direct measurements of thermal and acoustic transport using ultrafast spectroscopies. For the first time, we have measured a significant modulation – up to 631% – in the thermal conductance of twisted graphene by reducing phonon transmissions as a function of Moiré angles, while a high acoustic transmission maintains across all twist configurations. By comparing experiments with first‐principles calculations using density functional theory and molecular dynamics simulations, mode‐dependent phonon transmission between monolayer graphene are quantified based on the angle alignment of phonon band structures. We investigate mode‐specific phonon transmission and attribute the pronounced polarizing effect to the distortion over the coupling phase space especially from flexural phonon modes. The modeling results agree with experimental data, verifying the dominant tuning mechanisms in adjusting phonon transmission from high‐frequency thermal modes while negligible effects on low‐frequency acoustic modes near Brillouin zone center. This study offers crucial insights into the fundamental thermal transport in Moiré structures, opening avenues for the invention of advanced thermal devices and new design methodologies based on manipulations of vibrational band structures and phonon spectra.This article is protected by copyright. All rights reserved

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Nonequilibrium phonon mean free paths in anharmonic chains

Cited by 35 publications

References 44 publications

Thermal conductivity decomposition in two-dimensional materials: Application to graphene

Thermal conductivity decomposition in two-dimensional materials: Application to graphene

Remarkable Reduction of Interfacial Thermal Resistance in Nanophononic Heterostructures

Moiré Pattern Controlled Phonon Polarizer Based on Twisted Graphene

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