Anomalous Temperature Induced Transition and Convergence of Thermal Conductivity in Germanene Monolayer

Abstract

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 the long-scale characteristic timescale ${\tau }_2$ obtained from double exponential fitting of the heat current autocorrelation function. Phonon mode analysis using normal mode decomposition indicates that a redshift in ZO phonons reduces the acoustic-optical phonon gap, causing an overlap, enhances the phonon-phonon scattering, driving the anomalous scaling behavior. Moreover, nonequilibrium simulations find a convergent thermal conductivity of germanene with sample size, in agreement with mode coupling theory, owing to the high scattering of ZA phonons due to the inherent buckling of germanene.

arXiv commentTo appear in Phys. Chem. Chem. Phys

References in corpus (17)

• Two and one-dimensional honeycomb structures of silicon and germanium
• Thermal conduction in classical low-dimensional lattices
• Phonon Transport in Single-Layer Transition Metal Dichalcogenides: a First-Principles Study
• Phononic thermal properties of two-dimensional materials
• Application of silicene, germanene and stanene for Na or Li ion storage: A theoretical investigation
• First-Principles Prediction of Phononic Thermal Conductivity of Silicene: a Comparison with Graphene
• Functionalized Germanene as a Prototype of Large-Gap Two-Dimensional Topological Insulators
• Unexpected phonon-transport properties of stanene among 2D group-IV materials from \textit{ab initio}
• DynaPhoPy: A code for extracting phonon quasiparticles from molecular dynamics simulations
• Thermal conductivity decomposition in two-dimensional materials: Application to graphene
• Tensile Strains Give Rise to Strong Size Effects for Thermal Conductivities of Silicene, Germanene and Stanene
• Tunable band gap in germanene by surface adsorption
• How to Improve The Accuracy of Equilibrium Molecular Dynamics For Computation of Thermal Conductivity?
• Phonons and Thermal Conducting Properties of Borocarbonitride (BCN) Nanosheets
• Modeling Interlayer Interactions and Phonon Thermal Transport in Silicene Bilayer
• Transferability of interatomic potentials for germanene (2D germanium)
• Extreme Suppression of Thermal Conductivity in Monolayer Beryllene

Cited by in corpus (1)

• Tunable Interfacial Thermal Conductance in Graphene/Germanene van der Waals Heterostructure using an Optimized Interlayer Potential