Thermal expansion in multiple layers of graphene

TL;DR

This paper uses the nonequilibrium Green's function method to study how the number of layers and substrate interaction strength affect the thermal expansion coefficient in multilayer graphene.

Contribution

It provides a theoretical analysis of the impact of layer number and substrate interaction on graphene's thermal expansion, revealing conditions for increasing or decreasing CTE.

Findings

CTE can increase or decrease with layer number depending on substrate interaction strength

When substrate interaction is weaker than inter-layer interaction, CTE increases with layers

When substrate interaction is stronger, CTE decreases with layers

Abstract

In this file, we apply the nonequilibrium Green's function method to calculate the coefficient of thermal expansion (CTE) in multiple layers of graphene. We focus on the effect from different layer number $N$. Our main prediction is that: the increase of $N$ can either enhance or weaken CTE, depending on the strength of the substrate interaction $\gamma$. If $\gamma < \epsilon$, where $\epsilon$ is the inter-layer interaction, the CTE will increase with increasing $N$. Otherwise, if $\gamma > \epsilon$, CTE will decrease with increasing $N$.