标题： 锗烯单层中的热导率异常转变 显示英文标题

标题： Anomalous Transition in Thermal Conductivity in Germanene Monolayer

摘要： 我们报告了在临界温度$T_c = 350 \, \text{K}$附近，锗烯单层中热导率的异常温度诱导转变。平衡分子动力学模拟显示，在$T_c$以下呈现$\kappa \sim T^{-2}$标度，而在$\kappa \sim T^{-1/2}$以上呈现标度，与常规的$\kappa \sim T^{-1}$行为形成对比。这种异常标度与从热流自相关函数的双指数拟合得到的长尺度特征时间尺度$\tau_2$相关。使用正常模分解的声子模式分析表明，TA 声子的红移减少了声学-光学声子间隙，增强了声子-声子散射，从而驱动了异常标度行为。此外，非平衡模拟发现，由于锗烯固有的弯曲结构导致 ZA 声子的高散射，锗烯的热导率随着样品尺寸的增大而收敛，这与模式耦合理论一致。 显示英文摘要

摘要： We report an anomalous temperature-induced transition in thermal conductivity in germanene monolayer around a critical temperature $T_c = 350 \, \text{K}$. Equilibrium molecular dynamics simulations reveal a transition from $\kappa \sim T^{-2}$ scaling below $T_c$ to $\kappa \sim T^{-1/2}$ above, contrasting with conventional $\kappa \sim T^{-1}$ behavior. This anomalous scaling correlates with long-scale characteristics timescale $\tau_2$ obtained from double exponential fitting of heat current autocorrelation function. Phonon mode analysis using normal mode decomposition indicates that a redshift in TA phonons reduces the acoustic-optical phonon gap, enhancing the phonon-phonon scattering and driving the anomalous scaling behavior. Moreover, non equilibrium simulations find a convergent thermal conductivity of germanene with sample size, in agreement with mode coupling theory, owing to high scattering of ZA phonons due to the inherent buckling of germanene.