论文标题
有偏分子连接的非热振动
Non-thermal vibrations in biased molecular junctions
论文作者
论文摘要
我们使用主方程方法研究了电流携带模型分子连接的振动统计。特别是，我们专注于使用有效温度$ t _ {\ rm eff} $表征振动模式的非平衡稳态状态的有效性。我们确定单个$ t _ {\ rm eff} $无法完全描述一个振动状态的情况。在这种情况下，不同振动状态之间的概率分布不会遵循玻尔兹曼类型。因此，振动模式的实际熵（自由能）低于$ t _ {\ rm eff} $给出的相应热值，这表明可以从这些状态中提取额外的工作。我们的结果对于研究纳米级系统热力学的非热振动状态及其在纳米级热发动机中的使用将很有用。
We study vibrational statistics in current-carrying model molecular junctions using master equation approach. Especially, we concentrate on the validity of using an effective temperature $T_{\rm eff}$ to characterize the nonequilibrium steady state of a vibrational mode. We identify cases where a single $T_{\rm eff}$ can not fully describe one vibrational state. In such cases, the probability distribution among different vibrational states does not follow the Boltzmann type. Consequently, the actual entropy (free energy) of the vibrational mode is lower (higher) than the corresponding thermal value given by $T_{\rm eff}$, indicating extra work can be extracted from these states. Our results will be useful for the study of non-thermal vibrational state in thermodynamics of nanoscale systems, and its usage in nanoscale heat engines.
