A Substitutional Quantum Defect in WS_2 Discovered by High-Throughput Computational Screening and Fabricated by Site-Selective STM Manipulation

Point defects in two-dimensional materials are of key interest for quantuminformation science. However, the parameter space of possible defects isimmense, making the identification of high-performance quantum defectsvery challenging. Here, we perform high-throughput (HT)first-principlescomputational screening to search for promising quantum defects within WS2,which present localized levels in the band gap that can lead to bright opticaltransitions in the visible or telecomregime. Our computed database spansmore than 700 charged defects formed through substitution on the tungstenor sulfur site. We found that sulfur substitutions enable the most promisingquantum defects. We computationally identify the neutral cobalt substitutionto sulfur (Co-S(0)) and fabricate it with scanning tunneling microscopy (STM). TheCo(S)(0) electronic structure measured by STM agrees withfirst principles andshowcases an attractive quantum defect. Our work shows how HT computa-tional screening and nanoscale synthesis routes can be combined to designpromising quantum defects