Sudden Suppression of Electron-Transmission Peaks in Finite-Biased Nanowires

Negative differential conductance (NDC) is expected to be an essential property to realize fast switching in future electronic devices. We here present a thorough analysis on electron transportability of a simple atomic-scale model consisting of square prisms, and clarify the detailed mechanism of the occurrence of NDC phenomenon in terms of the changes of local density of states upon applying bias voltages to the electrodes. Boosting up bias voltages, we observe sudden suppression of transmission peaks which results in NDC behavior in the current-voltage characteristic. This suppression is explained by the fact that when the bias voltage exceeds a certain threshold, the conduction channels contributing to the current flow are suddenly closed up to deny the electron transportation.