Photoluminescence Lineshapes for Color Centers in Silicon Carbide from Density Functional Theory Calculations

TL;DR

This study uses density functional theory to analyze the photoluminescence lineshapes of color centers in silicon carbide, revealing the influence of phonons and vibrational modes, aiding quantum technology applications.

Contribution

It provides a detailed theoretical analysis of defect photoluminescence in SiC, connecting vibrational properties with optical signatures, which was previously lacking.

Findings

Defect lineshapes are influenced by bulk phonons and localized vibrational modes.

Good agreement with experimental data on photoluminescence spectra.

Theoretical insights assist in identifying defect signatures for quantum applications.

Abstract

Silicon carbide with optically and magnetically active point defects offers unique opportunities for quantum technology applications. Since interaction with these defects commonly happens through optical excitation and de-excitation, a complete understanding of their light-matter interaction in general and optical signatures, in particular, is crucial. Here, we employ quantum mechanical density functional theory calculations to investigate the photoluminescence lineshapes of selected, experimentally observed color centers (including single vacancies, double vacancies, and vacancy impurity pairs) in 4H-SiC. The analysis of zero-phonon lines as well as Huang-Rhys and Debye-Waller factors are accompanied by a detailed study of the underlying lattice vibrations. We show that the defect lineshapes are governed by strong coupling to bulk phonons at lower energies and localized vibrational modes at higher energies. Generally, good agreement to the available experimental data is obtained, and thus we expect our theoretical work to be beneficial for the identification of defect signatures in the photoluminescence spectra and thereby advance the research in quantum photonics and quantum information processing.