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PGI-1 Talk: Rik Broekhoven

Model for probing the flip-flop evolution of atomic spin 1/2 dimers with a tunneling microscope

30 Sep 2020 11:30

TU Delft, Netherlands


With the recent realization of electron spin resonance in tunneling microscopy it has become possible to probe coherent evolution in single magnetic adatoms. Improved models are required in order to characterize the inevitable decay in the form of relaxation and decoherence of these evolutions. Here, the first steps are made towards a model for the free coherent coupled evolution of Ti-dimers on MgO.

The Bloch-Redfield master equation is used without the common secular approximation. To decrease complexity, only Kondo interaction with the surface is taken into account. First, in order to verify the model a single atom is considered, for which the characteristic relaxation and decoherence times are known from experiment. Based on these results the model is rescaled.

Next, results are reported for a perfectly tuned dimer, which coincide with previous experimental and theoretical efforts. It is found that the perfectly tuned dimer is protected from pure dephasing caused by Kondo interaction. On top of this, by comparing with results derived from the same equation with additional secular approximation, it is discovered that secular approximation breaks down for large mismatch in the coupling to the surface.

This highlights the importance of this more exact model for different binding Ti-dimers.


Prof. Dr. Samir Lounis
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