Electronic and Magnetic Properties of Graphite Quantum Dots

TL;DR

This paper investigates the electronic and magnetic behaviors of multilayer graphite quantum dots, highlighting how their properties depend on shape, layer parity, and edge structure, with special focus on triangular zig-zag edged dots.

Contribution

It provides new insights into the size, shape, and edge effects on the electronic and magnetic properties of multilayer graphite quantum dots, especially for triangular zig-zag edged structures.

Findings

Shape and edge structure significantly influence electronic states.

Triangular MQDs exhibit unique zero-energy states and susceptibility behavior.

Edge-localized states cause distinctive magnetic responses.

Abstract

We study the electronic and magnetic properties of multilayer quantum dots (MQDs) of graphite in the nearest-neighbor approximation of tight-binding model. We calculate the electronic density of states and orbital susceptibility of the system as function of the Fermi level location. We demonstrate that properties of MQD depend strongly on the shape of the system, on the parity of the layer number and on the form of the cluster edge. The special emphasis is given to reveal the new properties with respect to the monolayer quantum dots of graphene. The most interesting results are obtained for the triangular MQD with zig-zag edge at near-zero energies. The asymmetrically smeared multi-peak feature is observed at Dirac point within the size-quantized energy gap region, where monolayer graphene flakes demonstrate the highly-degenerate zero-energy state. This feature, provided by the edge-localized electronic states results in the splash-wavelet behavior in diamagnetic orbital susceptibility as function of energy.