SINGLE-ELECTRON-CHARGING EFFECT CONTROLLED BY THE DISTANCE BETWEEN A SUBSTRATE AND A LIQUID-CRYSTAL MOLECULE

Single-electron-charging effects in a minuscule liquid-crystal molecule cannot be described in terms of a single-parameter-the capacitance. We performed a molecular-orbital-calculation to explain unequal Coulomb-staircase-edge spacings observed at room temperature. Since Coulomb blockade is a phenomenon associated with electron tunneling, it is describable using a transition probability from the initial state to the final state, where the initial state is the state before an electron enters into a molecule and the final state is the state after an electron enters into the molecule. When the applied electric field strength to the molecule overcomes an energy increase in the final state, the transition probability increases abruptly. This causes the Coulomb staircase edges. The effective charge confined within a molecule is determined by the distance between a molecule and a substrate.