Artificial crystals: Triggering topological order on demand

• Applicant: Dr. Carmine Ortix
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2015 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 276476674

Topological insulators are new states of quantum matter that hold great potential for use in transistors, memory devices and magnetic sensors that are highly energy efficient and require less power. These new materials have fundamentally challenged our common classification of materials in terms of electrical conductors and insulators. Topological insulators, indeed, act as both insulators and conductors, with their interior preventing the flow of electrical currents, while their surfaces or edges allow the movement of a charge. Most importantly, this charge movement is immune to scattering events, in which electrons deviate from their trajectories, resulting in dissipation and hence power consumption. Nature, however, offers us a large number of conventional insulators and electrical conductors while only a few materials have been firmly established as topological insulators, thereby hindering the exploitation of these novel states of quantum matter in next-generation electronic devices. In this project, we aim for a proof-of-principle demonstration that topological insulating states can be triggered on demand in man-made artificial crystal superstructures consisting of conventional building blocks. The feasibility of this concept will be theoretically explored by investigating topological quantum phase transitions in graphene and semiconducting thin films superlattices, which can be manufactured with cutting-edge nanotechnologies, as well as in ultracold atomic gases in one-dimensional optical superlattices. On the one hand, our investigations will represent an important advance in the fundamental comprehension of topological states of quantum matter. On the other hand, our new concept will set a stage for the generation of bottom-up versatile platforms for topological electronics.

• DFG Programme: Research Fellowships
• International Connection: Netherlands
• Host: Professorin Dr. Cristiane de Morais Smith