Artificial Material with Negative Thermal Expansion: A Simple Geometrical Approach

TL;DR

This paper presents a simple geometrical model for designing materials with negative thermal expansion by using Lennard-Jones potentials and specific atomic arrangements.

Contribution

It introduces a novel approach to designing NTE materials based on atomic layer arrangements and Lennard-Jones potential parameters.

Findings

Atomic layer arrangements can induce NTE behavior.

Specific Lennard-Jones parameter conditions lead to NTE.

A simple geometrical model explains NTE in layered materials.

Abstract

In the paper we report the modeling and design of material which has a negative thermal expansion (NTE). The basic assumption is a potential between the atoms in the material can be approximated by a Lennard-Jones potential (6-12) and the dominant interaction is only between nearest neighbors. We show that the material formed by alternating atomic layers wherein each layer contains a type of atom, and geometry of the arrangement of atoms is triangular, may experience an NTE when sigma_AA = sigma_BB = sigma_AB, epsilon_AA = epsilon_BB < epsilon_AB/4 are satisfied, where sigma_ij and epsilon_ij are Lennard-Jones parameters