Transport through evanescent waves in ballistic graphene quantum dots

TL;DR

This paper investigates how evanescent wave transport in graphene quantum dots varies with geometry and lattice structure, revealing geometry-dependent transmission behaviors and valley-dependent effects at atomic scales.

Contribution

It provides a detailed analysis of evanescent wave transport in graphene quantum dots with different shapes, highlighting the influence of geometry and lattice details on transmission.

Findings

Transmission is suppressed when leads connect to same sublattice edges.

Exponential decay of transmission in rectangular dots with lead distance.

Power-law decay of transmission in circular dots.

Abstract

We study the transport through evanescent waves in graphene quantum dots of different geometries. The transmission is suppressed when the leads are attached to edges of the same majority sublattice. Otherwise, the transmission depends exponentially on the distance between leads in rectangular dots, and as a power law in circular dots. The transmission through junctions where the transmitted and reflected currents belong to the opposite valley as the incoming one depends on details of the lattice structure at distances comparable to the atomic spacing.