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 de...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 onmeasurable 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.展开更多
基金supported by the National Research,Development,and Innovation Office of Hungary within the Quantum Information National Laboratory of Hungary(Grant No.2022-2.1.1-NL-2022-00004)within grants FK 135496 and FK 145395+2 种基金V.I.also acknowledges the support from the Knut and Alice Wallenberg Foundation through the WBSQD2 project(Grant No.2018.0071)Z.B.and A.P.acknowledge the financial support of the János Bolyai Research Fellowship of the Hungarian Academy of SciencesThe computations were enabled by resources provided by the National Academic Infrastructure for Supercomputing in Sweden(NAISS)and the Swedish National Infrastructure for Computing(SNIC)at NSC,partially funded by the Swedish Research Council through grant agreements no.2022-06725 and no.2018-05973.The authors also acknowledge KIFÜfor awarding us computational resources at the Komondor supercomputer in Hungary.
文摘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 onmeasurable 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.
