Discovery of Tunable Quantum Anomalous Hall Octet
- Bernal bilayer graphene is a naturally occurring system with neither spin-orbit coupling nor moiré complex.
- Quantum anomalous Hall (QAH) octet, i.e., eight states exhibiting quantum Hall effect at zero magnetic field, was theoretically predicted and experimentally observed.
- Ferromagnetism, ferroelectricity, and QAH effect coexist and cooperate in these competing ground states, thus switchable via magnetic/electric field and carrier sign.
- Bilayer graphene offers a potential platform for quantum information, quantum computing, and quantum sensing.
- Few-layer quasi-1D materials such as Bi4I4 and Bi4Br4have been predicted to be the time-reversal counterpart !