论文标题
多体绿色的功能方法用于晶格热传输
Many-body Green's function approach to lattice thermal transport
论文作者
论文摘要
了解复杂晶体中热传输的最新进展突出了带间隧道过程介导的热传导的重要作用，带间隧道过程在重叠的声子带（即能量差异小于其宽度）之间出现。这些过程最近以不同的方式描述了这些过程，这些过程依赖于Wigner或Green-Kubo形式主义，从而导致了显然不同的结果，这些结果质疑了热流操作员的定义。在这里，我们基于Kubo公式，阐明了类比以及与最近引入的Wigner或Green-kubo配方的差异，将热传输的描述扩展到原子振动过度阻尼的原子振动，在此将声子Quasiparticle quasiparticle胶片图片分解。我们依靠对具有超低电导率的复杂晶体的第一原理计算来比较上述方法中获得的热导率，这表明至少在准粒子状态下，对于实际应用，差异可忽略不计。
Recent progress in understanding thermal transport in complex crystals has highlighted the prominent role of heat conduction mediated by interband tunneling processes, which emerge between overlapping phonon bands (i.e. with energy differences smaller than their broadenings). These processes have recently been described in different ways, relying on the Wigner or Green-Kubo formalism, leading to apparently different results which question the definition of the heat-current operator. Here, we implement a full quantum approach based on the Kubo formula, elucidating analogies and differences with the recently introduced Wigner or Green-Kubo formulations, and extending the description of thermal transport to the overdamped regime of atomic vibrations, where the phonon quasiparticle picture breaks down. We rely on first-principles calculations on complex crystals with ultralow conductivity to compare numerically the thermal conductivity obtained within the aforementioned approaches, showing that at least in the quasiparticle regime the differences are negligible for practical applications.
