Observation of spin-polarized Anderson state around charge neutral point in graphene with Fe-clusters

Abstract

The pristine graphene described with massless Dirac fermion could bear topological insulator state and ferromagnetism via the band structure engineering with various adatoms and proximity effects from heterostructures. In particular, topological Anderson insulator state was theoretically predicted in tight-binding honeycomb lattice with Anderson disorder term. Here, we introduced physi-absorbed Fe-clusters/adatoms on graphene to impose exchange interaction and random lattice disorder, and we observed Anderson insulator state accompanying with Kondo effect and field-induced conducting state upon applying the magnetic field at around a charge neutral point. Furthermore, the emergence of the double peak of resistivity at nu = 0 state indicates spin-splitted edge state with high effective exchange field (>70T). These phenomena suggest the appearance of topological Anderson insulator state triggered by the induced exchange field and disorder.