Science Daily April 9. 2024
Moiré systems made from stacked two-dimensional materials host correlated and topological states that can be electrically controlled with applied gate voltages. One prevalent form of topological state that can occur are Chern insulators that display a quantum anomalous Hall effect. An international team of researchers (USA – UC Berkeley, Lawrence Berkeley National Laboratory, Japan) manipulated Chern domains in an interaction-driven quantum anomalous Hall insulator made from twisted monolayer–bilayer graphene and observed chiral interface states at the boundary between different domains. By tuning the carrier concentration, they stabilized neighbouring domains of opposite Chern number that then provided topological interfaces devoid of any structural boundaries. According to the researchers their analysis confirms the chiral nature of observed interface states and determine the characteristic length scale of valley polarization reversal across neighbouring Chern domains… read more. TECHNICAL ARTICLE
Local characterization of gate tunable Chern number for tMBLG QAH states… Credit: Nature Physics, 13 March 2024