Superconductivity of electron-hole pairs in a double layer graphene system in a quantizing magnetic field
D.V. Fil and L.Yu. Kravchenko
Institute for Single Crystals of the National Academy of Sciences of Ukraine 60 Lenin Ave., Kharkov 61001, Ukraine
Received June 3, 2009
The state with a spontaneous interlayer phase coherence in a graphene based bilayer quantum Hall system is studied. This state can be considered as a gas of superfluid electron-hole pairs with the components of the pair belonging to different layers. Superfluid flux of such pairs is equivalent to two electrical supercurrents in the layers. It is shown that the state with the interlayer phase coherence emerges in the graphene system if a certain imbalance of the
Landau level filling factors of the layers is created. We obtain the temperature of transition into the superfluid state, the maximum interlayer distance at which the phase coherence is possible, and the critical values of the supercurrent. The advantages of use of graphene systems instead of GaAs heterostructures for the realization of the bilayer electron-hole superconductivity are discussed.
PACS: 71.35.Ji Excitons in magnetic fields; magnetoexcitons; PACS: 73.21.–b Electron states and collectiveexcitations in multilayers, quantum wells,mesoscopic, and nanoscale systems; PACS: 73.63.–b Electronic transport in nanoscale materials and structures.