Ground-state properties of nanographite systems with zigzag-shaped edges

TL;DR

This paper investigates the ground-state properties of nanographite systems with zigzag edges, revealing a spin-singlet Mott insulator state with robust edge states and finite charge and spin gaps, using advanced computational methods.

Contribution

It demonstrates that electron-electron interactions lead to a Mott insulating ground state with persistent edge states in nanographite with zigzag edges, providing new insights into their electronic properties.

Findings

Ground state is a spin-singlet Mott insulator.

Edge states are robust against electronic correlations.

Finite charge and spin gaps are present.

Abstract

A \pi-electron network in nanographite systems with zigzag edges exhibits strongly localized edge states, which are expected to have peculiar properties. We study effects of electron-electron interactions on ground-state properties of the systems by means of the weak-coupling renormalization group and the density-matrix renormalization-group method. It is shown that the ground state is a spin-singlet Mott insulator with finite charge and spin gaps. We also find that the edge states are robust against the electronic correlations, resulting in edge effective spins which can flip almost freely. The schematic picture for the low-energy physics of the systems is discussed.