Dresden 2026 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

HL: Fachverband Halbleiterphysik

HL 16: Focus Session: Quantum Emitters in 2D Semiconductors

HL 16.3: Invited Talk

Tuesday, March 10, 2026, 10:30–11:00, POT/0081

Resolving atomic and electronic structure of point defects in MoS₂ by first-principles calculations and scanning tunneling microscopy — •Hannu-Pekka Komsa — University of Oulu, Oulu, Finland

A unique advantage of 2D materials is that the defects in them are always at or very near to the surface, which can be highly beneficial in quantum emitter and quantum sensing applications. Importantly, this also enables direct characterization and manipulation of the defects with surface-sensitive techniques, such as scanning tunneling microscopy (STM). Since STM probes mainly the electronic structure, defect identification often requires comparison to results from first-principles calculations.

I will present our recent investigations on the electronic structure of a few common point defects in 2D MoS₂, such as S vacancies, Mo and Fe adatoms, and C substitutional on S site, combining first-principles calculations and experimental STM results from University of Cologne and Karlsruhe Institute of Technology. I will first discuss the computational aspects that were found to be important in achieving good agreement with experiments. A careful analysis and comparison of the computational and experimental results then allow us to infer defect identity, charge state, defect-defect interactions, magnetic moment, and dynamic effects such as defect transformations among Jahn-Teller configurations, defect charging, and spin lifetimes. Finally, benefiting from the atomic manipulations inside STM, rational atom-by-atom fabrication of defect structures can be envisioned.

Keywords: First-principles calculations; Scanning tunneling microscopy; MoS2; point defect