Trapping photon-dressed Dirac electrons in a quantum dot studied by coherent two dimensional photon echo spectroscopy

TL;DR

This paper investigates how photon-dressed Dirac electrons can be localized in graphene quantum dots using two-dimensional photon echo spectroscopy, revealing excitonic states, dynamic gaps, and biexciton formation.

Contribution

It introduces a novel application of photon echo spectroscopy to study dressed Dirac electrons and excitonic effects in graphene quantum dots.

Findings

Identification of short-lived excitonic states via photon echo signals

Observation of dynamic gaps in two-dimensional spectra

Demonstration of Coulomb-induced biexciton formation

Abstract

We study the localization of dressed Dirac electrons in a cylindrical quantum dot (QD) formed on monolayer and bilayer graphene by spatially different potential profiles. Short lived excitonic states which are too broad to be resolved in linear spectroscopy are revealed by cross peaks in the photon-echo nonlinear technique. Signatures of the dynamic gap in the two-dimensional spectra are discussed. The effect of the Coulomb induced exciton-exciton scattering and the formation of biexciton molecules are demonstrated.