Ultimate impedance of coherent heat conduction in van der Waals graphene-MoS2 heterostructures
Ultimate impedance of coherent heat conduction in van der Waals graphene-MoS2 heterostructures
复制标题
DOI：
10.1016/j.mtphys.2020.100324
复制
发表时间：
2021-01-01
影响因子：
11.5
通讯作者：
Shiomi, J.
中科院分区：
文献类型：
--
作者：
Hu, S.;Ju, S.;Shiomi, J.
在一维超晶格中，通过相干声子控制热输运的研究越来越多。通常，组成材料的本征晶格结构的差异在制造过程中会产生界面无序，限制了相干声子输运操作。另一方面，范德华（vdW）异质结构的柔性集成和原子层间平滑性为相干声子输运操作提供了理想的平台。为了实现在室温下设计小型导热材料的最终目标，我们利用非平衡分子动力学模拟研究了不同堆叠顺序的vdW石墨烯- mos2异质结构中相干声子输运的可控性。利用基于贝叶斯优化的材料信息学，从数万个声子定位程度不同的候选材料中有效地识别出石墨烯和MoS2的最佳堆叠顺序。优化后的异质结构的导热系数（0.026 W/m-K）明显低于其构建块（原始MoS2和石墨烯）。此外，优化后的异质结构的热导率低于具有代表性的低热导率固体材料（非晶和无序晶体）和非晶聚合物。通过计算声子在最优异质结构中的传输量，分析不同无序堆叠异质结构中声子传输量的直方图分布规律，揭示了相干声子局部化的物理机制。通过对引入缺陷、改变系统厚度和温度的最优异质结构与原始石墨烯的对比研究，进一步验证了局域化的存在。我们的工作提供了对原子光滑vdW结构中相干声子输运行为的深入了解，这对声子的进一步发展至关重要。(C) 2020 Elsevier Ltd.版权所有。
There are growing efforts to control thermal transport via coherent phonons in one-dimensional superlattices. Typically, the difference in intrinsic lattice structures of the constituent materials generates an interface disorder during the fabrication process, limiting the coherent phonon transport manipulation. On the other hand, flexible integration and atomistic interlayer smoothness of a van der Waals (vdW) heterostructure provide an ideal platform for coherent phonon transport manipulations. Toward the ultimate goal of designing small thermal-conductivity materials at room temperature, herein we investigate the controllability of coherent phonon transport in vdW graphene-MoS2 heterostructures with different stacking orders using non-equilibrium molecular dynamics simulations. Using Bayesian optimization-based materials informatics, the optimal stacking order of graphene and MoS2 is efficiently identified from tens of thousands of candidates with varying degrees of phonon localization. The obtained thermal conductivity of the optimized heterostructure (0.026 W/m-K) is significantly lower than that of its building blocks (pristine MoS2 and graphene). Additionally, the optimized heterostructure has a thermal conductivity lower than those of representative low thermal conductivity solid materials (amorphous and disordered crystals), and the amorphous polymers. The underlying physical mechanism of coherent phonon localization is uncovered by calculating the phonon transmission in the optimum heterostructure and analyzing the histogram distribution pattern of the phonon transmissions in different disordered stacking heterostructures. The presence of localization is further validated by a comparative study of the optimum heterostructure to pristine graphene with introduced defects, changed the thickness and temperature of the system. Our work provides insight into the coherent phonons transport behavior in the atomistically smooth vdW structure, which is essential for further development of phononics. (C) 2020 Elsevier Ltd. All rights reserved.