A nanoelectromechanical model based on atomistic simulations including charge transfer was investigated. Classical molecular dynamics method combined with continuum electric models could be applied to a carbon-nanotube nanoelectromechanical memory device that could be characterized by carbon-nanotube bending performance by atomistic capacitive and interatomic forces. The capacitance of the carbon atom was changed with the height of the carbon atom. We performed MD simulations for a suspended (5,5) carbon-nanotube-bridge with the length of 11.567 nm (LCNT) and the depth of the trench of 0.9 ~ 1.5 nm (H). After the carbon-nanotube collided on the gold surface, the carbon-nanotube-bridge oscillated on the gold surface with amplitude of ~1 Å, and the amplitude gradually decreased. When H ≤ 1.3 nm, the carbon-nanotube-bridge continually contacted with the gold surface after the first collision. When H ≥ 1.4 nm, the carbon-nanotube-bridge stably contacted with the gold surface after several rebounds. As H increased, the threshold voltage linearly increased. As the applied bias increased, the transition time exponentially decreased at each trench depth. When H / LCNT was below 0.13, the carbon-nanotube nanoelectromechanical memories were permanent nonvolatile memory devices, whereas the carbon-nanotube nanoelectromechanical memories were volatile memory or switching devices when H / LCNT was above 0.14. The turn-on voltages and tunneling resistances obtained from our simulations are compatible to those obtained from previous experimental and theoretical results.
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