Thermal transport in MoS2 from molecular dynamics using different empirical potentials

Abstract

Thermal properties of molybdenum disulfide (MoS2) have recently attracted attention related to fundamentals of heat propagation in strongly anisotropic materials, and in the context of potential applications to optoelectronics and thermoelectrics. Multiple empirical potentials have been developed for classical molecular dynamics (MD) simulations of this material, but it has been unclear which provides the most realistic results. Here, we calculate lattice thermal conductivity of singleand multi-layer pristine MoS2 by employing three different thermal transport MD methods: equilibrium, nonequilibrium, and homogeneous nonequilibrium ones. These methods allow us to verify the consistency of our results and also facilitate comparisons with previous works, where different schemes have been adopted. Our results using variants of the Stillinger-Weber potential are at odds with some previous ones and we analyze the possible origins of the discrepancies in detail. We show that, among the potentials considered here, the reactive empirical bond order (REBO) potential gives the most reasonable predictions of thermal transport properties as compared to experimental data. With the REBO potential, we further find that isotope scattering has only a small effect on thermal conduction in MoS2 and the in-plane thermal conductivity decreases with increasing layer number and saturates beyond about three layers. We identify the REBO potential as a transferable empirical potential for MD simulations of MoS2 which can be used to study thermal transport properties in more complicated situations such as in systems containing defects or engineered nanoscale features. This work establishes a firm foundation for understanding heat transport properties of MoS2 using MD simulations.

Influence of thermostatting on nonequilibrium molecular dynamics simulations of heat conduction in solids

“…The NEMD results obtained by using Eqs. (28) and (27), on the other hand, deviate from the HNEMD results significantly. The relative errors caused by using Eqs.…”

“…(3), this amounts to using the temperature difference ∆T to calculate the thermal conductance: Figure 6 shows the total thermal conductance (integrated over the frequency) values obtained by using Eqs. (2) and (28) and different thermostatting methods. When Eq.…”

“…The relative errors caused by using Eqs. (28) and (27) decrease with increasing system length L. If one focuses on the diffusive regime with relatively long systems, using Eq. (27) will not result in large errors.…”

Temperature-dependent phonon spectrum of transition metal dichalcogenides calculated from the spectral energy density: Lattice thermal conductivity as an application

“…Furthermore, mixed modes and Raman forbidden modes restrict the measurement of frequencies of all phonon modes, and the obtained lifetimes rely on laser absorption. Classical molecular dynamics (MD) simulation is a powerful alternative to overcome all of the aforementioned problems, but its performance depends on the accuracy of interatomic potential [31]. In previous works, we have developed parameters for Stillinger-Weber (SW)-type potential for TMDs [32,33], and it was shown that the obtained thermal properties are in good agreement with first-principles calculations.…”

Mechanical Properties of Monolayer MoS2 with Randomly Distributed Defects

“…From the inter-atomic potential, we can obtain the new properties of any material like theoretical strength, elastic moduli, and Hooke's law. Stillinger-Weber (SW) potential employs an effective approach to describe the interactions in MoS 2 by considering all possible interactions between Mo and S [30][31][32].…”