An Exact Double Counting Scheme for Quantum Defect Embedding Theory

We recently introduced a many-body embedding scheme, called quantum defect embedding theory (QDET), to describe strongly correlated defect states in solids [1,2,3]. In QDET, an effective Hamiltonian for the localized states of defects in solids is derived within many-body perturbation theory, and the effect of the environment is included within the constrained random-phase approximation. Here, we present an exact diagrammatic double counting correction scheme for QDET which allows for a systematic convergence of the electronic structure of defects as a function of the size of the active space. We demonstrate the wide applicability of our formalism by presenting results for molecules and spin defects in wide-band-gap semiconductors.

[1] He Ma, Marco Govoni and Giulia Galli. npj Computational Materials 6, 1, 1-8 (2020)

[2] He Ma, Nan Sheng, Marco Govoni and Giulia Galli. J. Chem. Theory Comput. 2021, 17, 4, 2116–2125 (2020)

[3] Nan Sheng, Christian Vorwerk, Marco Govoni and Giulia Galli. preprint arXiv:2105.04736 (2021)