Long wavelength local density of states oscillations near graphene step edges

TL;DR

This study uses STM and spectroscopy to investigate LDOS oscillations near graphene step edges, revealing how quasiparticle energy influences oscillation wavelength and amplitude, and highlighting the unique decay behavior due to graphene's chiral Dirac fermions.

Contribution

It provides direct experimental evidence of LDOS oscillations in graphene near step edges and links these oscillations to the quasiparticle dispersion relation and chirality effects.

Findings

LDOS oscillations have wavelength and amplitude controlled by quasiparticle energy

Oscillations decay faster than in conventional metals due to graphene's chirality

Direct probe of graphene's dispersion relation through LDOS measurements

Abstract

Using scanning tunneling microscopy and spectroscopy, we have studied the local density of states (LDOS) of graphene over step edges in boron nitride. Long wavelength oscillations in the LDOS are observed with maxima parallel to the step edge. Their wavelength and amplitude are controlled by the energy of the quasiparticles allowing a direct probe of the graphene dispersion relation. We also observe a faster decay of the LDOS oscillations away from the step edge than in conventional metals. This is due to the chiral nature of the Dirac fermions in graphene.