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Wednesday, 29 April 2015

ICN2 Seminar: Dr Paolo Sessi on spin-orbit driven effects at surfaces

Dr Paolo Sessi, from University of Wuerzburg, offered a talk at the ICN2 about using scanning probe spectroscopies to visualize spin-orbit driven effects at surfaces and the obtained results. He was invited by Dr Aitor Mugarza, Group Leader of the Atomic Manipulation and Spectroscopy Group.

On Monday, April 27th, ICN2 hosted a seminar by Dr Paolo Sessi from University of Wuerzburg. He offered a talk entitled ‘Visualizing spin-orbit driven effects at surfaces by scanning probe spectroscopies’. The speaker was introduced by Dr Aitor Mugarza, Group Leader of the Atomic Manipulation and Spectroscopy Group, which remarked the highlights of the career of Dr Sessi.

Dr Paolo Sessi started his speech by talking about the Scanning Tunnelling Microscopy technique, standing out that it is an ideal tool to visualize boundary modes. After this, he got deep into the spin-orbit interaction and its intimately coupling and that, in recent years, condensed matter systems characterized by strong spin-orbit coupling have gain a lot of attention.

The speaker then presented recent results obtained in their group onto two prototypical systems: Rashba surfaces, where the strong spin-orbit interaction causes a spin splitting of a spin-degenerate electron gas in the presence of a structure inversion asymmetric potential, and topological insulators, where spin-orbit coupling acts as a kind of ’built-in magnetic field’ of a non-magnetic solid, that plays a role similar to the external magnetic field in the quantum Hall effect.

He also described experiments that through quantum interference allow not only to visualize the presence of unconventional edge states, but also to demonstrate their unusual properties. Finally, Dr Sessi discussed more recent efforts focused to their controlled manipulation, which can be achieved by directly coupling them to well defined charge and magnetic external perturbations.