Multiple magnetic barriers in graphene

TL;DR

This paper investigates charge transport in graphene subjected to inhomogeneous magnetic fields, analyzing magnetic barriers and superlattices to reveal transmission, conductance, and band structure effects.

Contribution

It introduces a detailed analysis of magnetic barrier sequences and superlattices in graphene, highlighting their impact on transmission and electronic band gaps.

Findings

Transmission increases with more barriers at fixed flux

Strong wave-vector filtering and resonances observed

Zero-energy band gap appears in periodic superlattices

Abstract

We study the behavior of charge carriers in graphene in inhomogeneous perpendicular magnetic fields. We consider two types of one-dimensional magnetic profiles, uniform in one direction: a sequence of N magnetic barriers, and a sequence of alternating magnetic barriers and wells. In both cases, we compute the transmission coefficient of the magnetic structure by means of the transfer matrix formalism, and the associated conductance. In the first case the structure becomes increasingly transparent upon increasing N at fixed total magnetic flux. In the second case we find strong wave-vector filtering and resonant effects. We also calculate the band structure of a periodic magnetic superlattice, and find a wave-vector-dependent gap around zero-energy.