Non-local linear-response functions for thermal transport computed with equilibrium molecular-dynamics simulation
Kevin Fernando, Patrick K. Schelling
备注：
Changes:: Title has changed. Previous assumptions about the denominator in Eq. 22 were incorrect. These are now found by MD simulation. The response functions are slightly changed as result. Figures 8-10 are changed. Time-dependence of the source is explained in Appendix A. More references were included to justify the approach used to derive Eq. 22
We establish an approach to compute linear-response functions to elucidate heat waves and non-local thermal transport. The theory is able to describe the response of a system to external heat sources that are nonuniform in space and time. The response functions are computed using equilibrium molecular-dynamics simulations of an Ar crystal modeled using the standard Lennard-Jones potential. It is shown that for low temperatures and short length scales, transport can be partially or even completely ballistic, with the response primarily limited by the group velocity of lattice waves. By contrast, at longer length scales and higher temperatures, the response functions correspond more closely to diffusive transport characteristic of Fourier's law. It is also shown how the effective thermal conductivity can be determined in a partially-ballistic regime. The results demonstrate the known reduction in the effective thermal conductivity observed when system dimensions are smaller than the mean-free path for lattice waves. Finally, we show how determination of the relevant response functions can be used to model heating of a crystal without requiring additional atomic-scale simulations. Differences between computed results and predictions from Fourier's law represent wave-like, partially-ballistic transport.
Local-field effects in current transport through molecular electronic devices: Current density profiles and local non-equilibrium electron distributions
Electronic Transport in Electron-Phonon Gas of Two-Dimensional Holstein's Organic Molecular-Crystal: Non-equilibrium Green's Function Formalism & Boltzmann Transport Framework (A Generalized Mathematical Solution)
DFT-based calculation of Coulomb blockade in molecular junction
通过单分子的量子输运对分子-电极接触的强度非常敏感。当分子结与外电极弱耦合时，电荷效应起重要作用（库仑阻塞机制）。在这一体系中，非平衡态格林函数通常用主方程方法代替，这使得密度泛函理论无法描述非平衡态下的库仑阻塞。去年，我们提出了一种将非平衡格林函数技术与运动方程方法相结合的方法。在此基础上，利用非平衡格林函数得到了库仑阻塞，并与主方程结果完全一致[Phys. Rev. B \textbf{76}，045408（2007）]。本文利用Ancestor方法，给出了一种在非平衡态DFT计算中引入库仑阻塞修正的新方法。并在对$toy$分子的计算中正确地得到了库仑阻塞的特性。
Spectral analysis of non-equilibrium molecular dynamics: spectral phonon temperature and phonon local non-equilibrium in thin films and across interfaces
Enabling Ab-Initio Molecular Dynamics under Bias: The CP2K+SMEAGOL Interface for Integrating Density Functional Theory and Non-Equilibrium Green Functions
Imperial College London（帝国理工学院）；University of Lincoln（林肯大学）
