PTB-News 2.2025 | The quantum anomalous Hall effect (QAHE) occurs in specific material systems such as magnetically doped topological insulators. In contrast to the conventional quantum Hall effect (QHE), the QAHE is characterized by the quantization of the Hall effect without an external magnetic field. In collaboration with the University of Würzburg, PTB has managed to prove by means of precision measurements that the Hall resistance of the QAHE matches the expected quantized value within a relative uncertainty of a few 10–9.
Source: Quantum Hall resistance without an external magnetic field
