New topological phases of matter have attracted in the last decades a lot of interest. These exotic phases are characterized by a global property, in opposition to the standard local order parameter of the Landau's theory. In particular, topological insulators is a new rising topic.Remarkably, the transverse conductivity in these systems is quantized in the energy gaps of the bulk and robust against perturbations: the current is transported by topologically protected chiral edge states. The Integer Quantum Hall effect is an example of topologically protected insulator. Here, the magnetic field induces the non-trivial topology. The Integer Quantum Hall effect has been observed in several lattice geometries such as the square lattice, the honeycomb. In this talk, we will focus on the effect of a magnetic on a quasi-crystal. We use several methods to characterize the topology of non-periodic system and find a surprising result: although the structure is not anymore periodic, the system has still topological properties.


Seminar, March 12, 2015, 12:00. Seminar Room

Hosted by Prof. Maciej Lewenstein