Study of magnetically doped nanocrystalline topological insulators

Magnetically doped topological insulators (TIs) are the materials platform for realising the quantum anomalous Hall effect (QAHE). The commonly used chalcogenide materials are plagued by a large, detrimental bulk carrier concentration, which can be naturally suppressed in nanocrystalline (nc) materials. We recently demonstrated, for the first time, that ncTIs can be magnetically doped with Mn and determined their magnetic ground state using XMCD at beamline I10 at Diamond. The next challenge is to raise the transition temperature through improved dopants and proximity coupling to a ferromagnetically ordered layer, to pave the way for future high temperature applications of the material. Here, we propose to study Cr and V doped films with much higher ordering temperatures, as well as those films on proximity coupling underlayers for enhancing the transition temperature further.