Theory of Graphene Chiral Quasiparticle LDOS maps

TL;DR

This paper develops a theoretical framework for understanding momentum space LDOS maps in graphene, highlighting the roles of intravalley and intervalley contributions and their dependence on disorder.

Contribution

It provides an analytic theory of graphene's LDOS maps in momentum space, explaining the features associated with Dirac points and disorder effects.

Findings

Intravalley LDOS features are centered near zero momentum.

Intervalley LDOS features are displaced by the wavevector K'-K.

LDOS features are sensitive to disorder types.

Abstract

We present a theory of momentum space local density-of-states (LDOS) maps N(q,omega) in graphene. The LDOS map has both intravalley contributions centered near zero momentum and reciprocal lattice vectors and intervalley contributions displaced by the wavevector K'-K which connects graphene's two distinct Dirac points. Using graphene's Dirac equation chiral quasiparticle continuum model, we obtain analytic results which explain the qualitative differences between these two LDOS map features. We comment on the sensitivity of both N(q,omega) features to the mix of atomic length scale and smooth disorder sources present in a particular graphene sample.