Gate tunable Kondo effect in magnetic molecule decorated graphene

The Kondo effect is one of the most widely studied many-body phenomena. Magnetic impurity decorated graphene is predicted to exhibit the Kondo effect with intriguing properties. Here we study the Kondo effect in Cobalt(II) phthalocyanine magnetic molecule decorated graphene by low temperature transport measurements. Spin-flip scattering and a logarithmic increase of resistance are observed, which confirms the Kondo effect. At a high carrier density, Kondo screening persists up to 20 K, suggesting a strong coupling between Dirac electrons and local magnetic moments of molecules. Decreasing the carrier concentration by a gate voltage results in a strong suppression of Kondo screening. Such tuning of Kondo screening can be used to turn on/off the local moment. Our results demonstrate a new Kondo system based on graphene. The significant gate tunability of the system may be used in spintronics.