In the quantum anomalous Hall effect, the edge states of a ferromagneticallydoped topological insulator exhibit quantized Hall resistance anddissipationless transport at zero magnetic field. Up to now, however, theresistance was experimentally assessed with standard transport measurementtechniques which are difficult to trace to the von-Klitzing constant R$_K$ withhigh precision. Here, we present a metrologically comprehensive measurement,including a full uncertainty budget, of the resistance quantization of V-doped(Bi,Sb)$_2$Te$_3$ devices without external magnetic field. We established as anew upper limit for a potential deviation of the quantized anomalous Hallresistance from RK a value of 0.26 +- 0.22 ppm, the smallest and most precisevalue reported to date. This provides another major step towards realization ofthe zero-field quantum resistance standard which in combination with Josephsoneffect will provide the universal quantum units standard in the future.
展开▼
