离子辐照对磷烯热导率的影响及其机制分析

通过离子辐照产生缺陷,可以非常有效地调控磷烯诸多物理性质.本文应用分子动力学方法模拟离子辐照磷烯的过程,给出了缺陷的形成概率与入射离子能量、离子种类以及离子入射角度之间的关系,并且应用非平衡态分子动力学计算辐照后磷烯热导率的变化.以缺陷形成概率为切入点,系统地研究了辐照离子的能量、辐照剂量、离子的种类以及离子的入射角度对磷烯热导率的影响.应用晶格动力学方法研究了空位缺陷对磷烯声子参与率的影响,并计算了声子局域模式的空间分布.基于量子微扰和键弛豫理论,指出空位缺陷明显降低磷烯热导率的最重要物理机制是空位缺陷附近的低配位原子对声子强烈散射.本文研究可为缺陷工程调控磷烯的热输运性质提供理论参考.

Effect of ion irradiation on thermal conductivity of phosphorene and underlying mechanism

Defects produced by ion irradiation can effectively modulate many physical properties of phosphorene.In this paper,the molecular dynamics method is used to simulate the ion irradiation process of phosphorene.The relations between the formation probability of defects and the energy of incident ions,ion species and incident angle of ions are revealed.The non-equilibrium molecular dynamics simulation is used to calculate the thermal conductivity of irradiated phosphorene.The effects of the energy of ions,the irradiation dose,the type of ions and the incident angle of ions on the thermal conductivity of phosphorene are systematically investigated.The influence of the vacancies on the phonon participation rate of phosphorene is studied by lattice dynamics method,and the spatial distribution of localized modes is demonstrated.According to the quantum-mechanical perturbation theory and bond relaxation theory,we point out that the dominant physical mechanism of vacancy defects which significantly reduce the thermal conductivity of phosphorene is the strong scattering of phonons by the low-coordinated atoms near the vacancies.This study provides a theoretical basis for tuning the heat transport properties of phosphorene by defect engineering.