Resonant tunneling is an efficient mechanism for charge transport through nanoscale conductance junctions due to the relatively high currents involved. However, continuous charging and discharging cycles of the nanoconductor during resonant tunneling often lead to mechanical instability. The realization of efficient nanoscale electronic components therefore depends to a large extent on the ability to mechanically stabilize them during resonant transport. In this work, we focus on single-molecule junctions, demonstrating that their mechanical stability during resonant transport can be increased by increasing the bias voltage. This counter-intuitive effect is attributed to the energy dependence of the molecule–lead coupling densities, which promote the rate of transport-induced cooling of molecular vibrations at higher voltages. The required energy dependence is characteristic of realistic electrodes (such as graphene), which cannot be modeled within the commonly invoked wide-band approximation. Our research provides new guidelines for the design of mechanically stable molecular devices operating in the regime of resonant charge transport and demonstrates these guidelines while considering realistic features of single-molecule junctions.

中文翻译：

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单分子连接的高压辅助机械稳定

由于涉及相对较高的电流，共振隧穿是用于电荷传输通过纳米级电导结的有效机制。然而，在共振隧穿期间纳米导体的连续充电和放电循环经常导致机械不稳定性。因此，有效的纳米级电子组件的实现在很大程度上取决于在共振传输过程中机械稳定它们的能力。在这项工作中，我们将重点放在单分子结上，这表明可以通过增加偏置电压来提高它们在共振传输过程中的机械稳定性。这种违反直觉的效应归因于分子-铅耦合密度的能量依赖性，从而提高了在较高电压下由运输引起的分子振动的冷却速率。所需的能量依赖性是真实电极（例如石墨烯）的特性，无法在通常调用的宽带近似中建模。我们的研究为设计在共振电荷传输机制下工作的机械稳定分子装置提供了新的指导方针，并在考虑单分子结的实际特征的同时证明了这些指导方针。