Current–current correlation function in the presence of chemical potential and magnetic field

详细

A (2+1)-dimensional electronic system is considered, in which the relation between the Green functions and the conductivity is used. A current–current correlation function, Π_μν(B), of the fermion system was obtained in the presence of nonquantized fermion magnetic field B, chemical potential η and gap m. Using this function one can obtain an expression for polarization operator calculated without the magnetic field. The result obtained can be applied for graphene.