Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg F-67034, France.
Institut de Recherche sur les Céramiques (IRCER), CNRS UMR 7315, Université de Limoges, Centre Européen de la Céramique, 12 rue Atlantis, 87068 Limoges, France.
J Chem Phys. 2023 Feb 28;158(8):084504. doi: 10.1063/5.0139590.
Thermal properties are expected to be sensitive to the network topology, and however, no clearcut information is available on how the thermal conductivity of amorphous systems is affected by details of the atomic structure. To address this issue, we use as a target system a phase-change amorphous material (i.e., GeSbTe) simulated by first-principles molecular dynamics combined with the approach-to-equilibrium molecular dynamics technique to access the thermal conductivity. Within the density-functional theory, we employed two models sharing the same exchange-correlation functional but differing in the pseudopotential (PP) implementation [namely, Trouiller-Martins (TM) and Goedecker, Teter, and Hutter (GTH)]. They are both compatible with experimental data, and however, the TM PP construction results in a Ge tetrahedral environment largely predominant over the octahedral one, although the proportion of tetrahedra is considerably smaller when the GTH PP is used. We show that the difference in the local structure between TM and GTH models impacts the vibrational density of states while the thermal conductivity does not feature any appreciable sensitivity to such details. This behavior is rationalized in terms of extended vibrational modes.
热性质预计对网络拓扑结构敏感，然而，关于非晶态系统的热导率如何受到原子结构细节的影响，目前还没有明确的信息。为了解决这个问题，我们选择一种相变非晶材料（即 GeSbTe）作为目标系统，通过第一性原理分子动力学模拟结合平衡分子动力学技术来获得热导率。在密度泛函理论中，我们采用了两个共享相同交换关联泛函但赝势（PP）实现不同的模型[即 Trouiller-Martins（TM）和 Goedecker、Teter、和 Hutter（GTH）]。它们都与实验数据兼容，然而，TM PP 的构建导致了四面体环境在八面体环境中占主导地位，尽管当使用 GTH PP 时四面体的比例要小得多。我们表明，TM 和 GTH 模型之间的局部结构差异会影响振动态密度，而热导率对这些细节没有任何明显的敏感性。这种行为可以根据扩展的振动模式来解释。
