Supplementary information files for: Anomalous thermal conductivity enhancement in low dimensional resonant nanostructures due to imperfections

Supplementary files for article: Anomalous thermal conductivity enhancement in low dimensional resonant nanostructures due to imperfections.Nanophononic metamaterials have broad applications in fields such as heat management, thermoelectric energy conversion, and nanoelectronics. Phonon resonance in pillared low-dimensional structures has been suggested to be a feasible approach to reduce thermal conductivity (TC). In this work, we study the effects of imperfections in pillared nanostructures based on graphene nanoribbons (GNR), using classical molecular dynamics simulations and harmonic lattice dynamics. The TC of perfect pillared GNR is only about 13% of that of pristine GNR due to the strong phonon resonant hybridization in pillared GNR. However, introducing imperfections such as vacancy defects and mass mismatch between the pillars and the base material, and alloy disorder in the pillars, can weaken the resonant hybridization and abnormally increase the TC. We show that both vacancy defects and mass mismatch can reduce the penetration of the resonant modes from the pillars into the base material, while the alloy disorder in the pillars can scatter the phonons inside them, which turns regular resonance into a random one with weaker hybridization. Our work provides useful insight into the phonon resonance mechanisms in experimentally relevant low dimensional nanostructures containing various imperfections.

补充文件：文章《由缺陷引起的低维谐振纳米结构异常热导率增强》的附件。纳米声子超材料在热管理、热电能量转换和纳米电子学等领域具有广泛的应用。研究表明，在柱状低维结构中，声子共振可能成为降低热导率（TC）的一种可行方法。在本研究中，我们利用经典分子动力学模拟和谐波晶格动力学，探讨了基于石墨烯纳米带（GNR）的柱状纳米结构中的缺陷对热导率的影响。完美的柱状 GNR 的热导率仅约为原始 GNR 的 13%，这归因于柱状 GNR 中强烈的声子共振杂交。然而，引入缺陷，如空位缺陷、柱子和基材之间的质量不匹配以及柱子中的固溶体无序，可以削弱共振杂交并异常增加热导率。我们发现，空位缺陷和质量不匹配可以减少共振模式从柱子渗透到基材的程度，而柱子中的固溶体无序则会使声子在其内部散射，将规则的共振转变为具有较弱杂交的随机共振。我们的研究为理解含有各种缺陷的实验相关低维纳米结构中的声子共振机制提供了有价值的见解。