Electronic Raman signatures of valley polarization, shell filling in graphene quantum dots

¹ Department of Physics and Astronomy, Georgia State University - Atlanta, GA 30303, USA
² Department of Physics and Astronomy, University of Manitoba - Winnipeg, Canada R3T 2N2

^a tapash@physics.umanitoba.ca

Received: 18 January 2011
Accepted: 16 May 2011

Abstract

Our theoretical studies of inelastic light scattering from few-electron graphene quantum dots indicate that the electronic Raman spectrum is governed both by the inter-electron Coulomb interaction and single-particle excitations. The spectral features depend on the number of electrons in the quantum dot (QD) and importantly, on the valley polarization. A closed-shell QD shows different properties in polarized and depolarized geometries. The intensity of the polarized Raman peaks is suppressed for closed-shell systems. We also show how Raman spectroscopy in graphene quantum dots can probe both single-particle and collective many-particle charge-density–type excitations.