Nonequilibrium Phenomena in Electron Tunneling in Normal Metal-Insulator-Metal Junctions

Structure in the conductance of normal metal-insulator-metal junctions at very low bias is explained through a nonequilibrium treatment of the tunneling process. In particular, the related peak in the derivative $\frac{d\sigma \mathrm{}\left(V\right)\mathrm{}}{\mathrm{dV}}$ is quantitatively accounted for by the blocking of otherwise available electron tunneling states due to the finite electron relaxation rates in the metal electrodes.