First-principles study of substitutional quantum defects in transition metal dichalcogenides

Transition metal dichalcogenides (TMDCs) have emerged as promising two-dimensional host materials for quantum defects with potential applications in quantum technologies. In this work, we perform first-principles study of transition metal doped monolayer MoS₂, MoSe₂, and WS₂, focusing on the substitutional doping on chalcogen sites. Density functional theory calculations with HSE06 functional were performed to determine the defect formation energies, charge transition levels, ground state symmetry and spin properties. For defects with triplet ground states, we discuss properties including spin-conserving optical transitions, intersystem crossing, and zero-field splitting. Finally, we will analyze the key descriptors that determine the stability and spin states of the substitutional defects in TMDCs.