First-principles theory of the luminescence lineshape for the triplet transition in diamond NV centre

TL;DR

This paper presents a first-principles computational approach to accurately model the vibronic structure and luminescence lineshape of the triplet optical transition in diamond NV centers, providing detailed insights into electron-phonon interactions.

Contribution

The work introduces a novel methodology combining hybrid functional calculations and a generating function approach to analyze electron-phonon coupling in NV centers.

Findings

Accurate spectral function of electron-phonon coupling obtained

Key parameters like Huang-Rhys and Debye-Waller factors accurately predicted

Identification of vibrational resonance at 65 meV as a localized mode

Abstract

In this work we present theoretical calculations and analysis of the vibronic structure of the spin-triplet optical transition in diamond nitrogen-vacancy centres. The electronic structure of the defect is described using accurate first-principles methods based on hybrid functionals. We devise a computational methodology to determine the coupling between electrons and phonons during an optical transition in the dilute limit. As a result, our approach yields a smooth spectral function of electron-phonon coupling and includes both quasi-localized and bulk phonons on equal footings. The luminescence lineshape is determined via the generating function approach. We obtain a highly accurate description of the luminescence band, including all key parameters such as the Huang-Rhys factor, the Debye-Waller factor, and the frequency of the dominant phonon mode. More importantly, our work provides insight into the vibrational structure of nitrogen vacancy centres, in particular the role of local modes and vibrational resonances. In particular, we find that the pronounced mode at 65 meV is a vibrational resonance, and we quantify localization properties of this mode. These excellent results for the benchmark diamond nitrogen-vacancy centre provide confidence that the procedure can be applied to other defects, including alternative systems that are being considered for applications in quantum information processing.