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Main Authors: Sun, Lei, Jónsson, Elvar Örn, Ivanov, Aleksei, Chen, Ji, Jónsson, Hannes
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2510.24144
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author Sun, Lei
Jónsson, Elvar Örn
Ivanov, Aleksei
Chen, Ji
Jónsson, Hannes
author_facet Sun, Lei
Jónsson, Elvar Örn
Ivanov, Aleksei
Chen, Ji
Jónsson, Hannes
contents The excited electronic states involved in the optical cycle preparation of a pure spin state of the negatively charged NV-defect in diamond are calculated using the HSE06 hybrid density functional and variational optimization of the orbitals. This includes the energy of the excited triplet as well as the two lowest singlet states with respect to the ground triplet state. In addition to the vertical excitation, the effect of structural relaxation is also estimated using analytical atomic forces. The lowering of the energy in the triplet excited state and the resulting zero-phonon line triplet excitation energy are both within 0.1 eV of the experimental estimates. An analogous relaxation in the lower energy singlet state using spin purified atomic forces is estimated to be 0.06 eV. These results, obtained with a hybrid density functional, improve on previously published results using local and semi-local functionals, which are known to underestimate the band gap. The good agreement with experimental estimates demonstrates how time-independent variational calculations of excited states using density functionals can give accurate results and, thereby, provide a powerful screening tool for identifying other defect systems as candidates for quantum technologies.
format Preprint
id arxiv_https___arxiv_org_abs_2510_24144
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Variational Calculations of the Excited States of the Charged NV-center in Diamond Using a Hybrid Functional
Sun, Lei
Jónsson, Elvar Örn
Ivanov, Aleksei
Chen, Ji
Jónsson, Hannes
Materials Science
Computational Physics
The excited electronic states involved in the optical cycle preparation of a pure spin state of the negatively charged NV-defect in diamond are calculated using the HSE06 hybrid density functional and variational optimization of the orbitals. This includes the energy of the excited triplet as well as the two lowest singlet states with respect to the ground triplet state. In addition to the vertical excitation, the effect of structural relaxation is also estimated using analytical atomic forces. The lowering of the energy in the triplet excited state and the resulting zero-phonon line triplet excitation energy are both within 0.1 eV of the experimental estimates. An analogous relaxation in the lower energy singlet state using spin purified atomic forces is estimated to be 0.06 eV. These results, obtained with a hybrid density functional, improve on previously published results using local and semi-local functionals, which are known to underestimate the band gap. The good agreement with experimental estimates demonstrates how time-independent variational calculations of excited states using density functionals can give accurate results and, thereby, provide a powerful screening tool for identifying other defect systems as candidates for quantum technologies.
title Variational Calculations of the Excited States of the Charged NV-center in Diamond Using a Hybrid Functional
topic Materials Science
Computational Physics
url https://arxiv.org/abs/2510.24144