Snake states in graphene quantum dots in the presence of a p-n junction

TL;DR

This paper explores magnetic interface states in graphene quantum dots with p-n junctions, revealing the interplay of edge and snake states, and identifying localized states at junction edges under magnetic fields.

Contribution

It introduces a detailed analysis of snake and edge states in graphene quantum dots with various p-n junction configurations using a tight-binding model.

Findings

Snake states arise at p-n junctions due to electron-hole overlap.

Localized dumb-bell shaped states occur at junction and zigzag edge crossings.

Magnetic flux and junction parameters significantly influence state behavior.

Abstract

We investigate the magnetic interface states of graphene quantum dots that contain p-n junctions. Within a tight-binding approach, we consider rectangular quantum dots in the presence of a perpendicular magnetic field containing p-n, as well as p-n-p and n-p-n junctions. The results show the interplay between the edge states associated with the zigzag terminations of the sample and the snake states that arise at the p-n junction, due to the overlap between electron and hole states at the potential interface. Remarkable localized states are found at the crossing of the p-n junction with the zigzag edge having a dumb-bell shaped electron distribution. The results are presented as function of the junction parameters and the applied magnetic flux.