Atomistic Simulations of Pure Tin Based on a New Modified Embedded-Atom Method Interatomic Potential

Abstract

A new interatomic potential for the pure tin (Sn) system is developed on the basis of the second-nearest-neighbor modified embedded-atom-method formalism. The potential parameters were optimized based on the force-matching method utilizing the density functional theory (DFT) database of energies and forces of atomic configurations under various conditions. The developed potential significantly improves the reproducibility of many fundamental physical properties compared to previously reported modified embedded-atom method (MEAM) potentials, especially properties of the β phase that is stable at the ambient condition. Subsequent free energy calculations based on the quasiharmonic approximation and molecular-dynamics simulations verify that the developed potential can be successfully applied to study the allotropic phase transformation between α and β phases and diffusion phenomena of pure tin.

Atomistic simulations of Ag–Cu–Sn alloys based on a new modified embedded-atom method interatomic potential

“…It has been reported that this method can significantly improve the overall performance of developed interatomic potentials [31][32][33]. In this study, we particularly extend our recent work [24] on the development of an interatomic potential for pure Sn-based on the force-matching method. We will present a detailed process for the development of interatomic potential that realizes the atomistic simulations of the Ag-Cu-Sn ternary system.…”

“…However, the MEAM potential for pure Sn developed by Ravelo and Baskes [23], which underlies the previous development of alloy potentials [17][18][19][20][21][22], exhibits deficiencies in reproducing properties of the β-Sn phase that is stable at ambient conditions [24]. Moreover, the previous MEAM potentials for alloy systems [17][18][19][20][21][22] were not developed considering various physical properties of binary and ternary alloy systems, and the optimization of potential parameters was not systematically performed.…”

“…We extended our previous optimization of the potential parameters for pure Sn [24] to obtain the potential parameters for the ternary Ag-Cu-Sn. We determined remaining unary (Ag and Cu), binary (Ag-Cu, Ag-Sn, and Cu-Sn), and ternary (Ag-Cu-Sn) parameters by fitting to the established DFT database of energies and forces.…”

“…The optimization started by specifying a radial cutoff distance, reference structures for target unary and binary systems, and fitting weights of each atomic configuration. The radial cutoff distance of 5.0 Å, which was previously reported to be large enough to reproduce various physical properties of pure Sn [24], was also used in this study. The reference structures for unary (Ag and Cu) and binary systems (Ag-Cu, Ag-Sn, Cu-Sn) were determined to be fcc and CsCl-type B2 structures, respectively.…”

“…For example, we can obtain a number of relevant candidate parameter sets for pure Ag and Cu, but optimization of the potential for pure Sn was a relatively difficult task. Therefore, we used a previously determined potential parameter set for pure Sn [24], which was obtained from a separate force-matching process targeting a specific unary system. For pure Ag and Cu, we did www.mrs.org/jmr Invited Feature Paper not perform separate fitting for unary parameters.…”