X-ray edge problem of graphene

TL;DR

This paper investigates the X-ray edge problem in graphene, revealing how the Dirac spectrum influences the singular response and how the Fermi energy affects the absorption rate, with potential experimental implications.

Contribution

It provides a detailed analysis of the crossover behavior and the dependence of the absorption exponent on scattering processes and Fermi energy in graphene.

Findings

Linear density of states suppresses Fermi liquid singularities at half-filling

Reappearance of Fermi liquid features away from half-filling

Absorption rate exponent varies with Fermi energy and scattering types

Abstract

The X-ray edge problem of graphene with the Dirac fermion spectrum is studied. At half-filling the linear density of states suppresses the singular response of the Fermi liquid, while away from half-filling the singular features of the Fermi liquid reappear. The crossover behavior as a function of the Fermi energy is examined in detail. The exponent of the power-law absorption rate depends both on the intra- and inter-valley scattering, and it changes as a function of the Fermi energy, which may be tested experimentally.