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2D materials are an exciting host to engineer atomic quantum systems by chemical design rules. In this colloquium, I will give an overview on our efforts to design and probe defect systems in monolayer transition metal dichalcogenides (TMDs) by means of chemical doping, Helium ion beam bombardment and atomic manipulation. By means of low-temperature scanning probe microscopy, we directly resolve the discrete electronic spectrum of single dopants in a charge neutral or ionized state and map out their associated defect orbitals [1-5]. Different types of defects reveal the interplay between chemical impurity states [1-3], multi-valley hydrogenic bound states [4,6], and electron-phonon coupling [1,7] at reduced dimensions. In particular, we will discuss the atomically controlled generation of carbon radical ions (CRIs) by hydrogen depassivation [7] and electrically driven photon emission from individual defects [8]. References: [1] B. Schuler et al., Phys. Rev. Lett. 123, 076801 (2019) [2] S. Barja et al., Nat. Commun. 10, 3382 (2019) [3] B. Schuler et al., ACS Nano 13, 10520 (2019) [4] M. Aghajanian et al., Phys. Rev. B 101, 081201(R) (2020) [5] E. Mitterreiter et al., Nano Lett. 20, 4437 (2020) [6] K. Cochrane et al., 2D Mater. 7, 031003 (2020) [7] K. Cochrane et al., arxiv: 2008.12196 [8] B. Schuler et al., Sci. Adv. 6, eabb5988 (2020)

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Bruno Schuler, Nanotech@surfaces Laboratory - EMPA, Switzerland
Zoom (https://uni-koeln.zoom.us/j/94292208989?pwd=OFh4Wi9yTW1SdmpueGo2aklUTlV1UT09)
Contact: Wouter Jolie