Partial preservation of chiral symmetry and colossal magnetoresistance in adatom-doped graphene

GONZALO USAJ; P. S. CORNAGLIA; C. A. BALSEIRO

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2014 vol. 89 p. 85405 - 85405

1098-0121

We analyze the electronic properties of adatom-doped graphene in the low-impurity-concentration regime. We focus on the Anderson localized regime and calculate the localization length ξ as a function of the electron doping and an external magnetic field. The impurity states hybridize with carbon´s pz states and form a partially filled band close to the Dirac point. Near the impurity band center, the chiral symmetry of the system´s effective Hamiltonian is partially preserved, which leads to a large enhancement of ξ. The sensitivity of transport properties, namely, Mott´s variable range hopping scale T0, to an external magnetic field perpendicular to the graphene sheet leads to a colossal magnetoresistance effect, as observed in recent experiments.