First-principles study of the thermoelectric properties of strained graphene nanoribbons

TL;DR

This study uses first-principles calculations to explore how tensile strain affects the thermoelectric efficiency of armchair graphene nanoribbons, revealing strain-induced enhancements in their figure of merit ZT for potential thermoelectric applications.

Contribution

It demonstrates that tensile strain can significantly improve the thermoelectric properties of AGNRs by altering their electronic and phononic structures, providing a new approach for optimizing thermoelectric materials.

Findings

Tensile strain increases ZT for N=3p and N=3p+2 AGNRs.

Strain modifies electronic structures and phonon dispersion relations.

Potential pathway for enhancing thermoelectric performance of graphene nanoribbons.

Abstract

We study the transport properties, in particular, the thermoelectric figure of merit ZT of armchair graphene nanoribbons, AGNR-N (for N=4-12, with widths ranging from 3.7 to 13.6~\AA) through strain engineering, where N is the number of carbon dimer lines across the AGNR width. We find that the tensile strain applied to AGNR-$N$ changes the transport properties by modifying the electronic structures and phonon dispersion relations. The tensile strain increases the ZT value of the AGNR-$N$ families with N=3p and N=3p+2, where $p$ is an integer. Our analysis based on accurate density-functional theory calculations suggests a possible route to increase the ZT values of AGNR-$N$ for potential thermoelectric applications.