QAHE: The QAHE offers metrologists (those interested in the studies of standards) the possibility of a quantum standard of resistance at a value of h/e2.  This is a manifestation of the topological complexity of 2D materials such as magnetically-doped TI’s and twisted multilayer graphene.  NIST has ongoing efforts in this topic in fabrication, measurement and high-accuracy determination.  However, there are various real-world issues that limit the temperature regime and electrical behavior.  We predict that high-frequency studies of the limits of QAHE, in both the GHz and THz ranges, can help us elucidate the energy splittings and mechanisms for the issues, and thus to improve the QAHE performance.  TI:  More generally, the same high-frequency investigations should allow us to probe the fascinating and complex physics underlying the wide variety of TI’s, including the  strongly interacting phases.

Principal Investigators: Neil Zimmerman, Curt Richter, Nikolai Zhitenev