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HL: Fachverband Halbleiterphysik
HL 44: 2D Materials: Electronic structure, excitations, etc. III (joint session O/HL/TT)
HL 44.2: Vortrag
Donnerstag, 12. März 2026, 15:15–15:30, HSZ/0204
Graphene-Enabled Mott--Metal Transition in Silicon Dangling Bonds — •Niclas Tilgner1, Siheon Ryee2, Zamin Mamiyev1, Philip Schädlich1, Christoph Tegenkamp1, Tim O. Wehling2, and Thomas Seyller1 — 1Institute of Physics, Chemnitz University of Technology, Germany — 2I. Institute of Theoretical Physics, University of Hamburg, Germany
Controlling emergent electronic phases in materials with strong Coulomb interactions remains a central challenge in condensed matter physics. Adatom lattices on semiconducting surfaces provide prototypical platforms for exploring such correlated phenomena. Recent advances have facilitated the synthesis of 2D Mott insulators in proximity to graphene (N. Tilgner et al 2025 2D Mater. 12 045022). Here, we demonstrate that alkali adsorption on a graphene/Si/SiC(0001) heterostructure -- where the Si layer hosts correlated dangling bonds -- enables controlled charge transfer to the Mott insulator. Beyond a critical carrier concentration, we observe a sudden collapse of the Mott gap, indicating a transition to a correlated metallic phase. Our results point to a finite proximity coupling between the Mott layer and graphene, as recently suggested by a theoretical study (N. Witt et al 2025 arXiv:2503.03700), which gives rise to nonlocal dynamical screening beyond simple electrostatics and provides a natural pathway for the observed phase transition.
Keywords: correlated physics; Mott insulator; correlated metal; screening; graphene