Semiquantitative theory of electronic Raman scattering from medium-size quantum dots

TL;DR

This paper presents a semiquantitative theoretical analysis of electronic Raman scattering in medium-sized quantum dots, accounting for Coulomb interactions, hole mixing, and resonance effects, to explain complex spectral features observed experimentally.

Contribution

It introduces a comprehensive theoretical framework combining RPA-like wave functions, Coulomb interactions, and hole mixing to analyze Raman spectra in quantum dots under resonance conditions.

Findings

Raman spectra show complex features with incident energy variation.

Resonances significantly affect Raman intensities of various excitations.

Theoretical results align with experimental observations.

Abstract

A consistent semiquantitative theoretical analysis of electronic Raman scattering from many-electron quantum dots under resonance excitation conditions has been performed. The theory is based on random-phase-approximation-like wave functions, with the Coulomb interactions treated exactly, and hole valence-band mixing accounted for within the Kohn-Luttinger Hamiltonian framework. The widths of intermediate and final states in the scattering process, although treated phenomenologically, play a significant role in the calculations, particularly for well above band gap excitation. The calculated polarized and unpolarized Raman spectra reveal a great complexity of features and details when the incident light energy is swept from below, through, and above the quantum dot band gap. Incoming and outgoing resonances dramatically modify the Raman intensities of the single particle, charge density, and spin density excitations. The theoretical results are presented in detail and discussed with regard to experimental observations.