Superconductivity in Graphene Induced by the Rotated Layer

Abstract

Recent discoveries in graphene bilayers revealed that when one of the layers is rotated, superconductivity emerges. We provide an explanation for this phenomenon . We find that due to the layer rotations, the spinors are modified in such way that a repulsive interaction, becomes attractive in certain directions. This result is obtained following a sequence of steps: when layer $2$ is rotated by an angle $\theta$ ,this rotation is equivalent to a rotation of an angle $-\theta$ of the linear momentum .Due to the discreet lattice, in layer $1$, the Fourier transform conserves the linear momentum $modulo$ the hexagonal reciprocal lattice vector . In layer $2$, due to the rotation, the linear momentum is conserved $modulo$ the $Moire$ reciprocal lattice vector . Periodicity is achieved at the $magical $ angles obtained from the condition of commensuration of the two lattices. We find that the rotations transform the spinors around the nodal points, such that a repulsive interaction becomes attractive, giving rise to superconductivity.