Anisotropic thermal conductivity and mechanical properties of phagraphene: a molecular dynamics study

Pereira, Luiz Felipe C.; Mortazavi, Bohayra; Makaremi, Meysam; Rabczuk, Timon

doi:10.1039/c6ra05082d

Cited by 74 publications

(41 citation statements)

References 42 publications

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“…We analyze the dependence of the cumulative lattice thermal conductivity with respect to the maximum phonon mean free path in the samples, which corresponds to the system length along the heat transport direction. From the behaviour of the cumulative conductivity with the system length we can estimate an effective phonon mean free path along each direction in a range of temperatures, using the following expression [67,68]:…”

Section: Resultsmentioning

confidence: 99%

Borophene hydride: a stiff 2D material with high thermal conductivity and attractive optical and electronic properties

et al. 2018

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Two-dimensional (2D) structures of boron atoms so called borophene, have recently attracted remarkable attention. In a latest exciting experimental study, a hydrogenated borophene structure was realized. Motivated by this success, we conducted extensive first-principles calculations to explore the mechanical, thermal conduction, electronic and optical responses of borophene hydride. The mechanical response of borophene hydride was found to be anisotropic in which it can yield an elastic modulus of 131 N/m and a high tensile strength of 19.9 N/m along the armchair direction. Notably, it was shown that by applying mechanical loading the metallic electronic character of borophene hydride can be altered to direct bandgap semiconducting, very appealing for the application in nanoelectronics. The absorption edge of the imaginary part of the dielectric function was found to occur in the visible range of light for parallel polarization. Finally, it was estimated that this novel 2D structure at the room temperature can exhibit high thermal conductivities of 335 W/mK and 293 W/mK along zigzag and armchair directions, respectively. Our study confirms that borophene hydride benefits an outstanding combination of interesting mechanical, electronic, optical and thermal conduction properties, promising for the design of novel nanodevices. 2Corresponding authors:

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Section: Resultsmentioning

confidence: 99%

Borophene hydride: a stiff 2D material with high thermal conductivity and attractive optical and electronic properties

et al. 2018

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“…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%

“…For the fixed boundary setup [6,32,[42][43][44], where the source and sink are at the two ends of the sample and separated by L, it is clear that L eff = L. For the periodic boundary setup [9,23,24,36,39] We stress that a single effective MFP is a crude representation of the transport length scales for the different phonons in a given component/branch. However, Eq.…”

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confidence: 99%

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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“…PG structures fracture at strains of 14% (10%) at 300 K (900 K). The literature value of the Young's modulus of PG membranes is 800 ± 14 GPa [2]. We found at 300K (900 K), 737 (713) and 808 (847) GPa along x and y directions, respectively.…”

Section: Resultsmentioning

confidence: 51%

Mechanical Properties of Phagraphene Membranes: A Fully Atomistic Molecular Dynamics Investigation

et al. 2018

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Recently, a new 2D carbon allotrope structure, named phagraphene (PG), was proposed. PG has a densely array of penta-hexa-hepta-graphene carbon rings. PG was shown to present low and anisotropic thermal conductivity and it is believed that this anisotropy should be also reflected in its mechanical properties. Although PG mechanical properties have been investigated, a detailed and comprehensive study is still lacking. In the present work we have carried out fully atomistic reactive molecular dynamics simulations using the ReaxFF force field, to investigate the mechanical properties and fracture patterns of PG membranes. The Young's modulus values of the PG membranes were estimated from the stress-strain curves. Our results show that these curves present three distinct regimes: one regime where ripples dominate the structure and mechanical properties of the PG membranes; an elastic regime where the membranes exhibit fully planar configurations; and finally a plastic regime where permanent deformations happened to the PG membrane up to the mechanical failure or fracture.

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Anisotropic thermal conductivity and mechanical properties of phagraphene: a molecular dynamics study

Cited by 74 publications

References 42 publications

Borophene hydride: a stiff 2D material with high thermal conductivity and attractive optical and electronic properties

Borophene hydride: a stiff 2D material with high thermal conductivity and attractive optical and electronic properties

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

Mechanical Properties of Phagraphene Membranes: A Fully Atomistic Molecular Dynamics Investigation

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