Interatomic potential for Si–O systems using Tersoff parameterization

Munetoh, Shinji; Motooka, Teruaki; Moriguchi, Koji; Shintani, Akira

doi:10.1016/j.commatsci.2006.06.010

Cited by 453 publications

(282 citation statements)

References 48 publications

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“…The interatomic interactions within Si, SiO 2 , and at the interface between the two materials are modeled by the Tersoff potential with the parameters developed by Munetoh et al 29,30 This potential has been used to study the phonon properties of a-SiO 2 and thermal/phonon transport across the Sija-SiO 2 interface. 20,21 Using the Tersoff potential, our MD simulation predicts a cubic lattice constant of 5.432 Å for Si.…”

Section: Simulation Methodsmentioning

confidence: 99%

Phonon interference in crystalline and amorphous confined nanoscopic films

Liang

Wilson

Keblinski

2017

Journal of Applied Physics

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Using molecular dynamics phonon wave packet simulations, we study phonon transmission across hexagonal (h)-BN and amorphous silica (a-SiO 2 ) nanoscopic thin films sandwiched by two crystalline leads. Due to the phonon interference effect, the frequency-dependent phonon transmission coefficient in the case of the crystalline film (Sijh-BNjAl heterostructure) exhibits a strongly oscillatory behavior. In the case of the amorphous film (Sija-SiO 2 jAl and Sija-SiO 2 jSi heterostructures), in spite of structural disorder, the phonon transmission coefficient also exhibits oscillatory behavior at low frequencies (up to $1.2 THz), with a period of oscillation consistent with the prediction from the two-beam interference equation. Above 1.2 THz, however, the phonon interference effect is greatly weakened by the diffuse scattering of higher-frequency phonons within an a-SiO 2 thin film and at the two interfaces confining the a-SiO 2 thin film. Published by AIP Publishing.

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Section: Simulation Methodsmentioning

confidence: 99%

Phonon interference in crystalline and amorphous confined nanoscopic films

Liang

Wilson

Keblinski

2017

Journal of Applied Physics

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“…This discovery opens up the possibility to further optimize the TC of ultra-thin silicon membranes by combining resonances with mass scattering, which affects phonons with higher frequency (ω 4 THz). We show that alloying the crystalline core of ultra-thin membranes with a small percentage of substitutional germanium atoms brings forth ultra-low TC in silicon membranes with technologically viable thickness [33].All TCs are calculated with equilibrium molecular dynamics (EMD) simulations at 300 K using LAMMPS [34] with interatomic interactions described by the widely used Tersoff potential [35][36][37]. The equations of motion are integrated with the velocity Verlet algorithm arXiv:1705.03143v1 [cond-mat.mtrl-sci]…”

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confidence: 99%

Native surface oxide turns alloyed silicon membranes into nanophononic metamaterials with ultralow thermal conductivity

et al. 2017

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A detailed understanding of the relation between microscopic structure and phonon propagation at the nanoscale is essential to design materials with desired phononic and thermal properties. Here we uncover a new mechanism of phonon interaction in surface oxidized membranes, i.e., native oxide layers interact with phonons in ultra-thin silicon membranes through local resonances. The local resonances reduce the low frequency phonon group velocities and shorten their mean free path. This effect opens up a new strategy for ultralow thermal conductivity design as it complements the scattering mechanism which scatters higher frequency modes effectively. The combination of native oxide layer and alloying with germanium in concentration as small as 5% reduces the thermal conductivity of silicon membranes to 100 time lower than the bulk. In addition, the resonance mechanism produced by native oxide surface layers is particularly effective for thermal condutivity reduction even at very low temperatures, at which only low frequency modes are populated.Controlling terahertz vibrations and heat transport in nanostructures has a broad impact on several applications, such as thermal management in micro-and nano-electronics, renewable energies harvesting, sensing, biomedical imaging and information and communication technologies [1][2][3][4][5][6][7][8]. Significant efforts have been made to understand and engineer heat transport in nanoscale silicon due to its natural abundance and technological relevance [9][10][11][12]. In the past decade researchers explored strategies to obtain silicon based materials with low thermal conductivity (TC) and unaltered electronic transport coefficients, so to achieve high thermoelectric figure of merit and enable silicon-based thermoelectric technology [11][12][13][14][15][16][17][18].From the earlier studies it was recognized that lowdimensional silicon nanostructures, such as nanowires, thin films and nano membranes feature a largely reduced TC, up to 50 times lower than that of bulk at room temperature. TC reduction becomes more prominent with the reduction of the characteristic dimension of the nanostructures [19][20][21][22]. Theory and experiments consistently show that surface disorder and the presence of disordered material at surfaces play a major role in determining the TC of nanostructures [12,[23][24][25]. However, a comprehensive understanding of the physical mechanisms underlying so large TC reduction is lacking. The effect of surface roughness and surface disorder on phonons has been so far interpreted in terms of phonon scattering [26][27][28][29][30], but scattering would not account for mean free path reduction of long-wavelength low-frequency modes. Recent theoretical work demonstrated that surface nanostructures, such as nanopillars at the surface of thin films or nanowires, can efficiently reduce TC through resonances, a mechanism that is intrinsically different from scattering [31,32]. Surface resonances alter directly phonon dispersion relations by hybridizing with prop...

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“…Tersoff parameter set for SiO 2 developed by Munetoh et al [15] , where r ij is the interatomic distance, ε ij and σ ij are the bond-order force field parameters, and χ is a dimensionless scaling factor (χ=1 by default). The LJ potential parameters for C-C bond are taken from Ref.…”

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confidence: 99%

Substrate coupling suppresses size dependence of thermal conductivity in supported graphene

2013

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Thermal conductivity κ of both suspended and supported graphene has been studied by using molecular dynamics simulations. Obvious length dependence is observed in κ of suspended single-layer graphene (SLG), while κ of supported SLG is insensitive to the length. The simulation result of room temperature κ of supported SLG is in good agreement with experimental value. In contrast to the decrease in κ induced by inter-layer interaction in suspended few-layer graphene (FLG), κ of supported FLG is found to increase rapidly with the layer thickness, reaching about 90% of that of bulk graphite at six layers, and eventually saturates at the thickness of 13.4 nm. More interestingly, unlike the remarkable substrate dependent κ in SLG, the effect of substrate on thermal transport is much weaker in FLG. The underlying physics is investigated and presented. Size dependence of thermal conductivity has been reported in various low dimensional nanomaterials [1][2][3][4][5][6][7] as well as in many low dimensional lattice models [8,9]. The most striking and controversial finding is that thermal conductivity in one dimensional systems (like nanotube and nanowire) diverges with length as power law, whereas it diverges logarithmically in two dimensional systems.As a novel two dimensional material, graphene has been the focus of intense studies in recent years [10][11][12]. It is found that thermal conductivity of suspended graphene [5, 6] and graphene nanoribbons (GNRs) [7] is also size dependent.However, in many device applications, graphene sheets are usually supported by and integrated with substrates. It is therefore of primary interest to understand the size dependence of thermal conductivity in supported graphene.In this paper, we systematically investigate the impacts of sample size, the thickness of graphene layers, and the substrate coupling strength on thermal conductivity of supported graphene on amorphous silicon dioxide (SiO 2 ) substrate.We employ molecular dynamics (MD) simulations in combination with phonon spectral analysis to elucidate the underlying physical mechanisms responsible for the heat conduction in supported graphene. Our study provides useful insights to better understand the thermal transport in supported graphene, which will be helpful in the design of graphene based devices.In our study, all MD simulations are performed by using LAMMPS package [13].Tersoff potential with optimized parameters for graphene [14] is adopted to model the intra-layer C-C interactions within the same graphene sheet. Tersoff parameter set for , where r ij is the interatomic distance, ε ij and σ ij are the bond-order force field parameters, and χ is a dimensionless scaling factor (χ=1 by default). The LJ potential parameters for C-C bond are taken from Ref. [16], and the LJ parameters for C-Si and C-O bonds are taken from Ref. [17]. The cut-off distance in LJ potential is set as 2.5σ ij for all kinds of bonds. Moreover, the neighbor list is dynamically updated every ten time steps, and each time step is set as 0.5 ...

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Interatomic potential for Si–O systems using Tersoff parameterization

Cited by 453 publications

References 48 publications

Phonon interference in crystalline and amorphous confined nanoscopic films

Phonon interference in crystalline and amorphous confined nanoscopic films

Native surface oxide turns alloyed silicon membranes into nanophononic metamaterials with ultralow thermal conductivity

Substrate coupling suppresses size dependence of thermal conductivity in supported graphene

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