Tungsten di-telluride (WTe2) has recently proven to be a promising material for the realization of topological states. These are regarded as the key to novel "spintronic" devices and quantum computers of the future due to their unique electronic properties. Physicists at Forschungszentrum Jülich have now been able to understand for the first time how the topological properties of multilayer WTe2 systems can be changed systematically by means of studies under a scanning tunneling microscope. The results have been published in the journal Nano Letters.