Strain induced edge magnetism at zigzag edge in graphene quantum dot

TL;DR

This study investigates how strain influences edge magnetism in graphene quantum dots, revealing potential for room temperature ferromagnetic behavior driven by electron interactions and strain effects.

Contribution

It provides the first unbiased numerical evidence that strain and Coulomb interactions can induce and enhance edge ferromagnetism in graphene quantum dots.

Findings

Strain and Coulomb interaction strengthen ferromagnetic fluctuations at zigzag edges.

Possible room temperature ferromagnetic transition in strained graphene quantum dots.

Enhanced edge magnetism could be useful for future applications.

Abstract

We study the temperature dependent magnetic susceptibility of a strained graphene quantum dot by using the determinant quantum Monte Carlo method. Within the Hubbard model on a honeycomb lattice, our unbiased numerical results show that a relative small interaction $U$ may lead to a edge ferromagnetic like behavior in the strained graphene quantum dot, and a possible room temperature transition is suggested. Around half filling, the ferromagnetic fluctuations at the zigzag edge is strengthened both markedly by the on-site Coulomb interaction and the strain, especially in low temperature region. The resultant strongly enhanced ferromagnetic like behavior may be important for the development of many applications.