Impact of the valence band on Rydberg excitons in cuprous oxide quantum wells

TL;DR

This paper develops a comprehensive Hamiltonian model for Rydberg excitons in cuprous oxide quantum wells, incorporating the full valence band structure to accurately predict energy shifts, degeneracy lifting, and optical transition strengths.

Contribution

It introduces a complete Hamiltonian based on the Luttinger-Kohn model for excitons in cuprous oxide quantum wells, advancing beyond simplified models.

Findings

Energy shifts due to valence band effects

Degeneracy lifting from band coupling

Calculated oscillator strengths for optical transitions

Abstract

The complex valence band structure of bulk cuprous oxide necessitates going beyond the parabolic approximation to precisely estimate exciton binding energies. The same is true for excitons in cuprous oxide quantum wells, for which many effects have been obtained so far only qualitatively within a hydrogenlike two-band model. Here, we derive the complete Hamiltonian for excitons in cuprous oxide quantum wells based on the Luttinger-Kohn model, taking into account the full complex valence band structure. Symmetry properties of the system are discussed. Numerical results based on the diagonalization of the Hamiltonian using B-spline functions reveal the energy shifts and the lifting of degeneracies due to the nondiagonal coupling terms of the complex valence band. The relative oscillator strengths of the excitonic transitions induced by circularly polarized light are also calculated.