Structure and Elastic properties of Titanium MXenes: evaluation of COMB3, REAXFF and MEAM force fields

TL;DR

This study evaluates the accuracy of three classical molecular dynamics force fields—COMB3, REAXFF, and MEAM—in predicting the structural and elastic properties of titanium MXenes, comparing results with DFT data and introducing new compressibility measurements.

Contribution

It provides a comparative assessment of multiple MD force fields for titanium MXenes, identifying the most reliable ones for structural and elastic property simulations.

Findings

Two REAXFF and two MEAM force fields accurately simulate MXenes properties.

First-time presentation of linear compressibility values for titanium MXenes.

Results enable better computational modeling of titanium MXenes for various applications.

Abstract

Titanium carbide and nitride MXenes are two-dimensional inorganic materials that exhibit noteworthy physical and chemical properties. These materials are considered for a variety of technological applications, ranging from energy harvesting to optical and biomedical applications. Given the growing interest in titanium MXenes, there is an expanding demand for computational studies to predict physical properties and behaviors under diverse physical conditions. Complex and large-scale systems necessitate computational methodologies that surpass the constraints imposed by ab initio calculations. In this regard, it is imperative to ascertain the reliability of the computational tools employed to simulate and predict the physical properties of titanium MXenes. In this study, the ability of three known classical molecular dynamics (MD) potentials to provide the structural and elastic properties of titanium carbide and nitride MXenes is evaluated. The MD potentials that were the focus of this study include the Charge-Optimized Many-Body (COMB3), the Reactive Force Field (REAXFF) and the Modified Embedded Atom Method (MEAM). These three potentials possess two or more sets of parameters, herein referred to as force fields, capable of simulating Ti-C and Ti-N systems. The MD results for the lattice parameter and thickness of the MXenes are then compared to those from DFT calculations found in the literature. A total of ten force fields were considered; of these, two REAXFF and two MEAM ones were identified as the most adequate to simulate both the structure and elastic properties of titanium MXenes. Additionally, the values for the linear compressibility of MXenes are presented for the first time. Consequently, researchers can utilize the obtained results to design novel MD-based computational studies of titanium MXenes, leveraging the established relative validity of the available force fields.