Topological insulator states coupled to spin degrees of freedom (TopEM)

The proposal addresses fundamental and material science aspects in the field of topological insulators coupled to magnetic atoms. The locking of the electron spin at a right-angle to its momentum in topological surface states introduces a highly interesting correlation between magnetic degrees of freedom and transport properties: 180° backscattering events are suppressed in time reversal symmetric conditions and electrons can propagate with large conductivities. According to theory, however, in the presence of external magnetic spin-flip channels, which break the system’s time reversal symmetry, such backscattering processes are allowed. We propose a consortium combining expertise in material growth, electronic and magnetic property measurements, as well as ab initio theory with the goal to design room temperature topological insulators with an intrinsic magnetic phase, with which the conductivity in topological surface states can be controlled with large on/off ratios.