Weiru Chen, John C Thomas, Yihuang Xiong, Zhuohang Yu, Da Zhou, Shalini Kumari, Zhongwei Dai, Joshua A Robinson, Mauricio Terrones, Archana Raja, Sinéad M Griffin, Alexander Weber-Bargioni, Geoffroy Hautier
Chalcogen vacancies in monolayer transition metal dichalcogenides (TMDs), such as WS2, play a crucial role in various applications ranging from optoelectronics and catalysis to quantum information science (QIS), making their identification and control essential. This study focuses on the WS2 single vacancy and vacancy pairs. Using first-principles computations, we investigate their thermodynamic stabilities and electronic structures. We identify an "on-top" divacancy configuration where two vacancies sit on top of each other to be the only energetically stable complex with a binding energy of 160 meV. We compute a small difference in electronic structure with a shift of the unoccupied state by 140 meV for the divacancy complex and make note of a similar shift observed experimentally.