Screened empirical bond-order potentials for Si-C

TL;DR

This paper introduces a general method to extend empirical bond-order potentials for Si-C by incorporating screening functions, enabling accurate modeling of brittle behavior and amorphous phases without refitting the potentials.

Contribution

A novel procedure to integrate screening functions with existing bond-order potentials without refitting, improving their accuracy for brittle and amorphous Si-C materials.

Findings

Correctly reproduces brittle material response

Improves description of amorphous phases

Applicable to multiple existing potentials

Abstract

Typical empirical bond-order potentials are short ranged and give ductile instead of brittle behavior for materials such as crystalline silicon or diamond. Screening functions can be used to increase the range of these potentials. We outline a general procedure to combine screening functions with bond-order potentials that does not require to refit any of the potential's properties. We use this approach to modify Tersoff's [Phys. Rev. B 39, 5566 (1989)], Erhart & Albe's [Phys. Rev. B 71, 35211 (2005)] and Kumagai et al.'s [Comp. Mater. Sci. 39, 457 (2007)] Si, C and Si-C potentials. The resulting potential formulations correctly reproduce brittle materials response, and give an improved description of amorphous phases.