Shot noise cross-correlations across single layer graphene structures are calculated with insulators separating a superconducting region. A new feature of specular crossed Andreev reflection comes into play due to the unique band structure of graphene. This gives rise to a rich structure in the states of the electric current flowing across the graphene sheet. We identified a parametric regime where { \em positive} shot noise cross-correlations of the current appear signifying entanglement. In contrast to previous proposals the sign of the cross-correlations can be easily tuned by the application of a gate voltage.
Categories: cond-mat.mes-hall cond-mat.mtrl-sci quant-ph