* Anisotropic topological insulators [1,2] :

Novel quantum states may be observed in the electronic and magnetic signatures of low-dimensional nanostructured systems, e.g. anisotropic topological insulators or metal-organic monolayers on metallic substrates with one- or two-dimensional electronic and magnetic structure.  For example, Dirac electrons with linear dispersion and high Fermi velocity may emerge on the surface on a topological insulator.  In the past, we studied the fascinating possibilities arising from spatial anisotropy resulting in different Fermi velocities in perpendicular directions and predicted this effect to occur on the surface of the topological insulator HgS [1].  Very recently, we calculated the anisotropic plasmon dispersion in such an anisotropic Dirac systems [2] where lines of constant plasmon energy in momentum space are shown on the Figure.  This plasmon anisotropy might be put to use in future applications such as plasmon wave guides.

* Metal-organic monolayers [3,4] :

On-surface polymerization of metal ions with organic precursor molecules on metallic surfaces [3,4], as studied experimentally by M. Abel and his group (Department EMONA), leads to a large variety of low-dimensional systems for which our group provides theoretical support in order to unveil exotic quantum states (like Weyl semi-metals, 1D or 2D spin liquids, topological states of matter, etc).  As an example we show the ab-initio calculated atomic structure of Fe zwitterionic quinone (Fe C₆O₂N₂H₄ ) polymer chains on the Au(110) surface [4]. Interestingly, in dependence of the chosen substrate (Ag(111) ot Au(110) a spin state transition of the local Fe spin has been found.

* Thermoelectrics Kondo boost [5] :

Our investigation of the thermoelectric transport through a double-orbital quantum dot in the Kondo regime [5] showed that transport properties and power generation may be strongly enhanced by the interplay of orbital degeneracy and Kondo physics. This setup outperforms not only the usual single-orbital quantum dot, but also devices in the Coulomb blockade regime. An experimentally relevant optimal operating point has been determined. It owes its stability to the Kondo effect and might even allow for a complete removal of the gate electrode. A comparison of the transport properties obtained from carefully implemented approximations relying solely on the transport coefficients with the fully nonlinear solution proves the robustness of the former up to large applied temperature bias for the systems under study, thus adding credibility to many works on nanoscale devices conducted within this framework.