Quasiparticle Interference and Landau Level Spectroscopy in Graphene in the presence of a Strong Magnetic Field

TL;DR

This paper calculates how impurities affect the local electronic states in graphene under strong magnetic fields, revealing specific interference patterns in Fourier space that can be observed via scanning tunneling spectroscopy.

Contribution

It introduces a detailed theoretical analysis of quasiparticle interference and Landau level effects in graphene with impurities under magnetic fields, linking to experimental STS measurements.

Findings

FT features at reciprocal lattice points due to low-energy quasiparticles

Wavevector cut-off at the observation energy

Potential for experimental observation via STS

Abstract

We present a calculation of the modulation in the Local Density Of electronic States (LDOS) caused by an impurity in graphene in the presence of external magnetic field. We focus on the spatial Fourier Transform (FT) of this modulation around the impurity. The FT due to the low energy quasiparticles are found to be nonzero over the reciprocal lattice corresponding to graphene. At these lattice spots the FT exhibits well-defined features at wavevectors that are multiples of the inverse cyclotron orbit diameter (see Figure 2) and is cut off at the wavevector corresponding to the energy of observation. Scanning Tunneling Spectroscopy (STS) on graphene and the energy-resolved FT fingerprint obtained therefrom may be used to observe the quasiparticle interference of Dirac particles in graphene in the presence of magnetic field.