Accurate and convergent energetics of color centers by wavefunction theory

Benedek, Zsolt and Ganyecz, Ádám and Pershin, Anton and Ivády, Viktor and Barcza, Gergely (2025) Accurate and convergent energetics of color centers by wavefunction theory. NPJ COMPUTATIONAL MATERIALS, 11 (1). No.-346. ISSN 2057-3960

Preview

Text s41524-025-01813-0.pdf - Published Version Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (1MB) | Preview

Abstract

The accurate description of in-gap states of point defects in semiconductors with significant multideterminant character presents a long-standing challenge for density functional theory (DFT) methods. In this study, we devise an ab initio methodology based on wavefunction theory (WFT) as a competing alternative approach. Specifically, we apply perturbation theory (NEVPT2) on top of a defect-localized many-body wavefunction (CASSCF). This quantum chemistry methodology, exemplified for the NV− center in diamond, is not only used for the calculation of energies and properties, but also for state-specific geometry optimization. By relaxing cluster models of increasing size and investigating convergence behavior, we accurately computed (i) the energy levels of NV− electronic states involved in the polarization cycle, (ii) the effect of Jahn-Teller distortion on measurable properties, (iii) the fine structure of ground and excited states, and (iv) the pressure dependence of zero-phonon lines. In addition, we predict hitherto uncharacterized high-lying excited states.

Actions (login required)

View Item