Dresden 2026 – scientific programme
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O: Fachverband Oberflächenphysik
O 17: Spins on surfaces at the atomic scale – Poster
O 17.12: Poster
Monday, March 9, 2026, 18:00–20:00, P2
Spin Screening in MoS2 Mirror Twin Boundaries on Graphene/Ir(110) — •Kuber Vyas, Tfyeche Tounsi, Jeison Fischer, Affan Safeer, Thomas Michely, and Wouter Jolie — II. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
Mirror twin boundaries (MTBs) are line defects that host confined states in the bandgap of monolayer MoS2(1). The confined states closest to the Fermi energy splits into a singly and a doubly occupied level separated by the Coulomb repulsion U, forming a spin-1/2 system. The spin of the singly occupied state is then screened by the electron bath present in the substrate below, giving rise to a Kondo resonance pinned to the Fermi energy.
In this work, we investigate spin screening in MoS2 MTBs grown on graphene/Ir(110) using low-temperature scanning tunnelling microscopy and spectroscopy. STS spectra recorded along the boundaries show two pronounced impurity peaks separated by the Coulomb energy U, together with a zero-bias feature which can be attributed to the Kondo resonance. MTBs on Gr/Ir(110) exhibit significantly broadened impurity-level widths, indicating strong hybridization γ with the electron bath provided by the graphene/Ir(110) substrate. This enhanced hybridization results in a Kondo temperature TK comparable to the measurement temperature (7 K), enabling us to study the phase transition between the Kondo singlet phase below and the magnetic phase above the Kondo temperature. [1] C. van Efferen et al, Nat. Phys. 20, 82-87 (2024)
Keywords: Kondo physics; 2d material; Scanning Tunneling Microscopy