Magnetic structure of hydrogen-induced defects on graphene

JORGE O. SOFO; GONZALO USAJ; PABLO S. CORNAGLIA; A. M. SUAREZ; ALEXANDER D. HERNANDEZ-NIEVES; C. A. BALSEIRO

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Año: 2012 vol. 85 p. 115405 - 115405

1098-0121

Using density-functional-theory (DFT), Hartree-Fock, exact-diagonalization, and numerical-renormalization group methods, we study the electronic structure of diluted hydrogen atoms chemisorbed on graphene. A comparison between DFT and Hartree-Fock calculations allows us to identify the main characteristics of the magnetic structure of the defect.We use this information to formulate an Anderson-Hubbard model that captures the main physical ingredients of the system while still allowing a rigorous treatment of the electronic correlations. We find that the large hydrogen-carbon hybridization puts the structure of the defect halfway between the one corresponding to an adatom weakly coupled to pristine graphene and that of a carbon vacancy. The impurity’s magnetic moment leaks into the graphene layer where the electronic correlations on the C atoms play an important role in stabilizing the magnetic solution. Finally, we discuss the implications for the Kondo effect.