Deep-center defects in semiconductors

A renewed interest has been recently devoted to the study of deep-center defects in materials for applications in emergent quantum technologies such as quantum sensing. The typical example of a deep-center defect is the nitrogen-vacancy (NV) center in diamond. The spin states of this defect can be optically manipulated at room temperature, which makes it attractive for magnetic sensing [1].
The aim of this work is to obtain a reference method to model the electronic properties of the NV-center in diamond for the purpose of magnetic sensing. Density Functional Theory (DFT) is widely used for the calculation of the electronic structure of defects [2]. However, the single Slater determinant nature of the DFT wavefunctions does not allow for the calculations of the many-body levels of some defects. In the present work I develop a Hubbard model for the NV-center with the model parameters calculated by wannierization of defect levels computed with DFT-GGA and HSE06 calculations in large supercells. I will show that the model enables access to the multideterminant defect levels.
[1] L Rondin et al, Rep. Prog. Phys. 77, 056503 (2014)
[2] A. Gali et al, Phys. Rev. B 77(15), 155206 (2008)