Empirical interatomic potentials optimized for phonon properties

Rohskopf, Andrew; Seyf, Hamid Reza; Gordiz, Kiarash; Tadano, Terumasa; Henry, Asegun

doi:10.1038/s41524-017-0026-y

Cited by 44 publications

(27 citation statements)

References 63 publications

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“…where f i (n) and f DFT i (n) are the force on the i-th atom in the n-th structure calculated from the empirical potential and DFT, respectively. The above fitness function is similar to those used in the potfit [49] and POPS [47] packages.…”

Section: B Genetic Algorithm As the Fitting Methodsmentioning

confidence: 99%

A minimal Tersoff potential for diamond silicon with improved descriptions of elastic and phonon transport properties

Fan¹,

Wang²,

Gu³

et al. 2019

J. Phys.: Condens. Matter

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Silicon is an important material and many empirical interatomic potentials have been developed for atomistic simulations of it. Among them, the Tersoff potential and its variants are the most popular ones. However, all the existing Tersoff-like potentials fail to reproduce the experimentally measured thermal conductivity of diamond silicon. Here we propose a modified Tersoff potential and develop an efficient open source code called GPUGA (graphics processing units genetic algorithm) based on the genetic algorithm and use it to fit the potential parameters against energy, virial and force data from quantum density functional theory calculations. This potential, which is implemented in the efficient open source GPUMD (graphics processing units molecular dynamics) code, gives significantly improved descriptions of the thermal conductivity and phonon dispersion of diamond silicon as compared to previous Tersoff potentials and at the same time well reproduces the elastic constants. Furthermore, we find that quantum effects on the thermal conductivity of diamond silicon at room temperature are non-negligible but small: using classical statistics underestimates the thermal conductivity by about 10% as compared to using quantum statistics. *

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Section: B Genetic Algorithm As the Fitting Methodsmentioning

confidence: 99%

A minimal Tersoff potential for diamond silicon with improved descriptions of elastic and phonon transport properties

Fan¹,

Wang²,

Gu³

et al. 2019

J. Phys.: Condens. Matter

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“…Lattice properties can also be computed using computationally lighter, but still reliable methods, such as carefully parameterized interatomic potentials. 23,24 A common drawback of these methods, however, is their limited transferability, and their use in a different environment from the one used for the parameterization is in principle questionable. Polytypism is a textbook case in this sense, and indeed it is not guaranteed that a potential parameterized to reproduce the properties of a ZB semiconductor works equally well with the WZ crystal.…”

Section: Methodsmentioning

confidence: 99%

Phonon transport across crystal-phase interfaces and twin boundaries in semiconducting nanowires

et al. 2019

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We combine state-of-the-art Green's-function methods and nonequilibrium molecular dynamics calculations to study phonon transport across the unconventional interfaces that make up crystal-phase and twinning superlattices in nanowires. We focus on two of their most paradigmatic building blocks: cubic (diamond/zinc blende) and hexagonal (lonsdaleite/wurtzite) polytypes of the same group-IV or III-V material. Specifically, we consider InP, GaP and Si, and both the twin boundaries between rotated cubic segments and the crystal-phase boundaries between different phases. We reveal the atomic-scale mechanisms that give rise to phonon scattering in these interfaces, quantify their thermal boundary resistance and illustrate the failure of common phenomenological models in predicting those features. In particular, we show that twin boundaries have a small but finite interface thermal resistance that can only be understood in terms of a fully atomistic picture. † Electronic supplementary information (ESI) available. See

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“…Also, since the bulk modulus is computed from the variation of energy with respect to the volume of the unit cell, the inclusion of these configurations ensure that the fitted parameters are able to reproduce the equilibrium lattice constant and the bulk modulus. Besides fitting to the energy surface, Rohskopf et al 23 proposed fitting to the forces on each atom and the harmonic and 3rd order interatomic force constants calculated from ab initio methods. Forces and force constants are first order and higher order derivatives of the energy surface ( ∂E ∂ri ,…”

Section: Electronic Structure and Phonon Dispersionmentioning

confidence: 99%

“…However, the bond lengths in bulk Sb 2 Te 3 are different from that of Bi 2 Te 3 , and using the same potential parameters for both would result in a strained Sb 2 Te 3 lattice. More recently, Rohskopf et al 23 used a genetic algorithm based optimization method to fit a combination of different functional forms of interatomic potentials for Si and Ge. Such modified potentials have been shown to predict the phonon properties well for Si and Ge.…”

Section: Introductionmentioning

confidence: 99%

Development of interatomic potentials for the complex binary compound Sb2Te3 and the prediction of thermal conductivity

2019

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Molecular dynamics (MD) simulation has emerged as a powerful predictive tool to study mechanical and thermal properties of materials, without the requirement for any fitting parameter inputs such as phonon relaxation time. However, the lack of suitable interatomic potentials for many complex materials greatly prohibits effective use of MD simulations to investigate properties of bulk materials and nanostructures. In this work, we use the method of fitting to an ab initio energy surface to develop interatomic potential parameters for the complex binary material antimony telluride, which has important applications in thermoelectric energy generation. Density-functional theory is used to calculate the ground state electronic structure of the Sb2Te3 crystal, following which the total energies of a series of artificially distorted lattice configurations are calculated to create the energy surface. A Morse potential functional form is fitted to the energy surface and experimental data, and the parameters are used to calculate the bulk crystal properties and phonon spectra using lattice dynamics. Our parameters are able to reproduce the lattice structure, elastic constants and acoustic phonon dispersion in good agreement with experimental data. Molecular dynamics simulations are performed using the fitted potential to calculate the thermal conductivity of bulk Sb2Te3 using the Green-Kubo method. The predicted thermal conductivity shows a 1/T variation in both in-plane and cross-plane directions with the results in the range of experimental measurements. Frequency domain normal mode analysis (FD-NMA) is used to calculate the modal phonon relaxation times and the accumulation of thermal conductivity with respect to phonon mean free path. The results show that phonons with mean free paths between 3 and 100 nm contribute to 80% of the total cross-plane thermal conductivity.

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Empirical interatomic potentials optimized for phonon properties

Cited by 44 publications

References 63 publications

A minimal Tersoff potential for diamond silicon with improved descriptions of elastic and phonon transport properties

A minimal Tersoff potential for diamond silicon with improved descriptions of elastic and phonon transport properties

Phonon transport across crystal-phase interfaces and twin boundaries in semiconducting nanowires

Development of interatomic potentials for the complex binary compound Sb2Te3 and the prediction of thermal conductivity

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