KELDYSH APPROACH FOR COULOMB-BLOCKADE IN DOUBLE-BARRIER STRUCTURES

We present a theoretical study of two small normal tunnel junctions co nnected in series and driven by a dc voltage source, using Keldysh's a pproach for the nonequilibrium state and taking the current continuity into account by adjusting the electrochemical potential mu in the isl and. The numerical results of the Coulomb Blockade of tunneling conduc tance show that the lowest order of the tunneling processes can explai n the experimental results qualitatively when the tunneling resistance R(T) is large compared with the resistance quantum R(Q) h/2e2.