The thermal conductivity of two-dimensional materials, such as graphene, typically decreases when tensile strain is applied, which softens their phonon modes. Here, we report an anomalous strain effect on the thermal conductivity of monolayer silicene, a representative low-buckled two-dimensional (LB-2D) material. ReaxFF-based molecular dynamics simulations are performed to show that biaxially stretched monolayer silicene exhibits a remarkable increase in thermal conductivity, by as much as 10 times the freestanding value, with increasing applied strain in the range of [0, 0.1], which is attributed to increased contributions from long-wavelength phonons. A further increase in strain in the range of [0.11, 0.18] results in a plateau of the thermal conductivity in an oscillatory manner, governed by a unique dynamic bonding behavior under extreme loading. This anomalous effect reveals new physical insights into the thermal properties of LB-2D materials and may provide some guidelines for designing heat management and energy conversion devices based on such materials.

中文翻译：

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反常应变对低屈曲二维硅烯导热系数的影响


当施加拉伸应变时，二维材料（例如石墨烯）的热导率通常会降低，从而软化其声子模式。在这里，我们报告了单层硅烯热导率的反常应变效应，单层硅烯是一种代表性的低屈曲二维（LB-2D）材料。基于 ReaxFF 的分子动力学模拟表明，随着施加应变在 [0, 0.1] 范围内增加，双向拉伸单层硅烯的导热系数显着增加，高达独立值的 10 倍，这归因于增加长波长声子的贡献。应变在 [0.11, 0.18] 范围内的进一步增加会导致热导率以振荡方式达到稳定状态，这是由极端负载下独特的动态粘合行为控制的。这种反常效应揭示了对 LB-2D 材料热性能的新物理见解，并可能为设计基于此类材料的热管理和能量转换设备提供一些指导。