Combined first-principles and experimental investigations of nearest neighbor defect complexes in monolayer tungsten disulfide

The availability of reliable quantum defects is a key component towards realizing quantum information science applications. Two-dimensional (2D) materials such as transition metal dichalcogenides (TMDs) emerge as a promising platform to host such quantum defects owing to their intrinsic quantum confinement nature, long expected spin coherence time and strong spin-orbit coupling (SOC). We focus on two most common point defects in monolayer tungsten disulfide (WS2): sulfur vacancy and carbon radical substitution on the sulfur site. For each of them we look at a single defect as well as the nearest neighbor defect complexes. By taking into account the non-unique exact exchange fraction in low dimensional materials, we employ hybrid functionals with SOC to examine the thermodynamic stabilities and the electronic structures of these nearest neighbor defect complexes and compare them with single defect cases. Our results on their stabilities and effects on the electronic structures, combined with experimental characterizations, shed light on future endeavors towards defect engineering and fabricating quantum defects in TMDs.