In the quantum anomalous Hall effect, the edge states of a ferromagnetically doped topological insulator exhibit quantized Hall resistance and dissipationless transport at zero magnetic field. Up to now, however, the resistance was experimentally assessed with standard transport measurement techniques which are difficult to trace to the von-Klitzing constant RK with high precision. Here, we present a metrologically comprehensive measurement, including a full uncertainty budget, of the resistance quantization of V-doped (Bi,Sb)2Te3 devices without external magnetic field. We established as a new upper limit for a potential deviation of the quantized anomalous Hall resistance from RK a value of 0.26 +- 0.22 ppm, the smallest and most precise value reported to date. This provides another major step towards realization of the zero-field quantum resistance standard which in combination with Josephson effect will provide the universal quantum units standard in the future.
@article{arxiv.1710.04090,
title = {Zero-field quantum anomalous Hall metrology as a step towards a universal quantum standard unit system},
author = {Martin Goetz and Kajetan M. Fijalkowski and Eckart Pesel and Matthias Hartl and Steffen Schreyeck and Martin Winnerlein and Stefan Grauer and Hansjoerg Scherer and Karl Brunner and Charles Gould and Franz J. Ahlers and Laurens W. Molenkamp},
journal= {arXiv preprint arXiv:1710.04090},
year = {2018}
}