Comparison of Quantum Embedding Methods on Fe Impurity in AlN

The ongoing development of quantum embedding methods, particularly that of density matrix embedding theory (DMET) [1] and quantum defect embedding theory (QDET), [2] has established this class of techniques as a promising approach for describing the excited states of point defects in solids. However, the various embedding methods each rely on their own sets of approximations and systematic comparisons of different approaches remain scarce. Furthermore, certain classes of defects such as transition metal defects in semiconductors are relatively less explored with embedding theories and recent research has suggested they may be a challenging test of such methods’ predictive power.[3] In this work, we apply both DMET with the Pyscf code and QDET as implemented within the West code to the Fe impurity in AlN, systematically assessing the influence of methodological parameters and comparing vertical excitation energy predictions.



[1] A. Mitra et al. J. Phys. Chem Lett. 12, 11688 (2021).



[2] Sheng et al. J. Chem. Theory Comput. 18, 3512 (2022).



[3] Muechler et al. Phys. Rev. B. 105, 235104 (2022).