Complex role of strain engineering of lattice thermal conductivity in hydrogenated graphene-like borophene induced by high-order phonon anharmonicity

Abstract

Strain engineering has been used as a versatile tool for regulating the thermal transport in various materials as a result of the phonon frequency shift. On the other hand, the phononic bandgap can be simultaneously tuned by the strain, which can play a critical role in wide phononic bandgap materials due to the high-order phonon anharmonicity. In this work, we investigate the complex role of uniaxial tensile strain on the lattice thermal conductivity of hydrogenated graphene-like borophene, by using molecular dynamics simulations with a machine learning potential. Our findings highlight a novel and intriguing phenomenon that the thermal conductivity in the armchair direction is non-monotonically dependent on the uniaxial armchair strain. Specifically, we uncover that the increase of phonon group velocity and the decrease of three-phonon scattering compete with the enhancement of four-phonon scattering under armchair strain, leading to the non-monotonic dependence. The enhanced four-phonon scattering originates from the unique bridged B-H bond that can sensitively control the phononic bandgap under armchair strain. This anomalous non-monotonic strain-dependence highlights the complex interplay between different mechanisms governing thermal transport in 2D materials with large phononic bandgaps. Our study offers valuable insights for designing innovative thermal management strategies based on strain.

Thermal Rectification in Graphene–Boron Nitride Nanotube Hybrid Structures: An Independent Control Mechanism for Forward and Backward Heat Flux

“…Ren et al studied the effect of moiré superlattice on heat transport in van der Waals heterojunctions and found that the moiré effect can flexibly regulate heat flow by affecting the atomic stress amplitude. He et al explored the complex role of strain engineering in regulating the lattice thermal conductivity of hydrogenated graphene-like borophene and found that strain applied in both armchair and zigzag directions can increase the anisotropy of thermal conductivity. In this study, we examined the impact of tensile and compressive strains on the heat flux and TR of GR-BNNTs, as depicted in Figure a.…”

Dual Substrate Effect of Silicon Substrate on Thermal Transport Characteristic of (14,14,14)‐Graphyne: Transformation from Conventional Suppressing Role to Abnormal Promoting Role

“…The mechanisms involved include the competition between group velocity and higher‐order phonon scattering. [ 51 ] In conclusion, the aforementioned methods hold promise for overcoming the negative substrate effects on heat transport in electronic devices.…”