Edge stability, reconstruction, zero-energy states and magnetism in triangular graphene quantum dots with zigzag edges

TL;DR

This study uses density functional theory to analyze the stability, reconstruction, and magnetic properties of zigzag edges in triangular graphene quantum dots, revealing the effects of hydrogen passivation on edge stability and magnetism.

Contribution

It provides new insights into how edge reconstruction and hydrogen passivation influence the stability and magnetic behavior of triangular graphene quantum dots.

Findings

Reconstructed pentagon-heptagon edges are more stable without hydrogen.

Hydrogen passivation favors ideal zigzag edges energetically.

Hydrogen passivation maintains zero-energy states, but magnetic properties differ.

Abstract

We present the results of ab-initio density functional theory based calculations of the stability and reconstruction of zigzag edges in triangular graphene quantum dots. We show that, while the reconstructed pentagon-heptagon zigzag edge structure is more stable in the absence of hydrogen, ideal zigzag edges are energetically favored by hydrogen passivation. Zero-energy band exists in both structures when passivated by hydrogen, however in case of pentagon-heptagon zigzag, this band is found to have stronger dispersion, leading to the loss of net magnetization.