Wouter Jolie

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Electrons are prone to strong correlations when confined into one-dimensional (1D) or 0D cavities. Many exotic ground states can emerge, depending on the type of interactions at play. Examples are Peierls transitions, Tomonaga-Luttinger liquids or Anderson impurities.
An ideal experimental testbed for the observation of correlated electronic behaviour are point defects and metallic mirror twin boundaries (MTBs) in two-dimensional semiconductors such as MoS2. These quantum objects have well-defined structural and electronic properties, are only weakly coupled to the environment and accessible to spatially resolved spectroscopic techniques such as scanning tunnelling microscopy (STM). In the first part of my talk, I will show that the confined quasiparticles within finite MoS2 MTBs transform into spin and charge excitations as described by the Tomonaga-Luttinger liquid theory of strongly interacting 1D electrons. In addition, a Kondo resonance emerges when the highest occupied state is filled by a single electron, in quantitative agreement with the Anderson impurity model. In the second part, I will focus on magnetic point defects, which can be created and manipulated on the atomic scale using STM. After quantifying the magnetic properties of isolated and coupled spins, I will show how one can study their spin dynamics using electron spin resonance STM (ESR-STM).

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Universität zu Köln
PH2
Contact: Erwann Bocquillon / Matteo Cacco