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 ν = 0 state indicates spin-splitted edge state with high effective exchange field (>70 T). These phenomena suggest the appearance of topological Anderson insulator state triggered by the induced exchange field and disorder.

Surface Engineering of Substrates for Chemical Vapor Deposition Growth of Graphene and Applications in Electronic and Spintronic Devices

“…211,212 With graphene surface adsorbed ferromagnetic clusters such as Fe (Figure 15c), strain and an exchange field would be induced at the same time. 203 Under a high magnetic field, a valley-polarized state and spin-polarized state existed simultaneously (Figure 15d), which had an important influence in the field of quantum transport. In recent years, graphene-based spin Hall devices continuously have attracted attention in this research area.…”

“…Furthermore, the enhancement of SOC was also observed in the exfoliated graphene decorated metal particles such as Ag and Au, which eliminated the possibility of graphene defects or contamination caused by the transfer process. Therefore, the proximity effect was the main reason for the enhancement of SOC, which arose from the hybridization of graphene π orbitals and Cu d orbitals. , With graphene surface adsorbed ferromagnetic clusters such as Fe (Figure c), strain and an exchange field would be induced at the same time . Under a high magnetic field, a valley-polarized state and spin-polarized state existed simultaneously (Figure d), which had an important influence in the field of quantum transport.…”

“…(c) Schematic illustration of graphene-based Hall-bar device with Fe clusters. (d) Resistivity as a function of V g measured at 2 K under various applied magnetic fields [(c,d) Reproduced from ref . Copyright 2020, Springer Nature, reproduced without any modification and licensed under CC BY 4.0, ].…”