Chen Renai, Craven Galen T
Theoretical Division and Center for Nonlinear Studies, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Entropy (Basel). 2024 Dec 30;27(1):18. doi: 10.3390/e27010018.
A stochastic energetics framework is applied to examine how periodically shifting the frequency of a time-dependent oscillating temperature gradient affects heat transport in a nanoscale molecular model. We specifically examine the effects that frequency switching, i.e., instantaneously changing the oscillation frequency of the temperature gradient, has on the shape of the heat transport hysteresis curves generated by a particle connected to two thermal baths, each with a temperature that is oscillating in time. Analytical expressions are derived for the energy fluxes in/out of the system and the baths, with excellent agreement observed between the analytical expressions and the results from nonequilibrium molecular dynamics simulations. We find that the shape of the heat transport hysteresis curves can be significantly altered by shifting the frequency between fast and slow oscillation regimes. We also observe the emergence of features in the hysteresis curves such as pinched loops and complex multi-loop patterns due to the frequency shifting. The presented results have implications in the design of thermal neuromorphic devices such as thermal memristors and thermal memcapacitors.
应用随机能量学框架来研究周期性改变随时间变化的振荡温度梯度的频率如何影响纳米级分子模型中的热传输。我们特别研究了频率切换，即瞬间改变温度梯度的振荡频率，对连接到两个热浴的粒子所产生的热传输滞后曲线形状的影响，每个热浴的温度都随时间振荡。推导了系统与热浴之间能量通量的解析表达式，解析表达式与非平衡分子动力学模拟结果之间具有良好的一致性。我们发现，通过在快速和慢速振荡模式之间切换频率，可以显著改变热传输滞后曲线的形状。我们还观察到由于频率切换，滞后曲线中出现了诸如收缩环和复杂多环模式等特征。所呈现的结果对热神经形态器件（如热忆阻器和热忆容器）的设计具有启示意义。
