Edge and Point-Defect Induced Electronic and Magnetic Properties in Monolayer PtSe2

Funding Information: J.L. and T.J. contributed equally to this work. The USF‐group acknowledges financial support from the NSF through award no. 2140038. A.V.K. thanks the German Research Foundation (DFG), projects KR 4866/2‐1, and KR 4866/7‐1 for the support. The authors further acknowledge the Gauss Centre for Supercomputing e.V. (www.gauss‐centre.eu) for providing computing time on the GCS Supercomputer HAWK at Höchstleistungsrechenzentrum Stuttgart (www.hlrs.de) and TU Dresden (Taurus cluster) for generous grants of CPU time. Publisher Copyright: © 2022 Wiley-VCH GmbH Edges and point defects in layered dichalcogenides are important for tuning their electronic and magnetic properties. By combining scanning tunneling microscopy (STM) with density functional theory (DFT), the electronic structure of edges and point defects in 2D-PtSe2 are investigated where the 1.8 eV bandgap of monolayer PtSe2 facilitates the detailed characterization of defect-induced gap states by STM. The stoichiometric zigzag edge terminations are found to be energetically favored. STM and DFT show that these edges exhibit metallic 1D states with spin polarized bands. Various native point defects in PtSe2 are also characterized by STM. A comparison of the experiment with simulated images enables identification of Se-vacancies, Pt-vacancies, and Se-antisites as the dominant defects in PtSe2. In contrast to Se- or Pt-vacancies, the Se-antisites are almost devoid of gap states. Pt-vacancies exhibit defect induced states that are spin polarized, emphasizing their importance for inducing magnetism in PtSe2. The atomic-scale insights into defect-induced electronic states in monolayer PtSe2 provide the fundamental underpinning for defect engineering of PtSe2-monolayers and the newly identified spin-polarized edge states offer prospects for engineering magnetic properties in PtSe2 nanoribbons.