Revealing Charge Transfer in Defect-Engineered 4H_b-TaS₂

We present a comprehensive first-principles investigation of defects in 4H_b-TaS₂. In this layered transition metal dichalcogenide, charge transfer between alternating Mott-insulating 1T and metallic 1H layers gives rise to exotic quantum phases such as the Kondo effect and topological superconductivity. Motivated by recent defect manipulation in 4H_b-TaS₂ via STM, we address their microscopic nature and impact on interlayer charge transfer. To this end, we systematically analyze 65 native defects and oxygen impurities using large-scale density functional theory (DFT) calculations. Our extensive dataset—compiled from STM simulations, defect formation energies, work functions, density of states, and charge transfer— establishes a foundational resource for future theoretical and experimental studies on defect engineering in 4H_b-TaS₂.