石墨烯声子平均自由程随温度变化规律研究  

Temperature-dependent phonon mean free path of graphene

作　　者：任晓霞[1] 贺长安[1] 查小婷 周恩民[1] 郑瑞伦[1] REN Xiaoxia;HE Chang’an;ZHA Xiaoting;ZHOU Enmin;ZHENG Ruilun(College of Electronic and Electrical Engineering, Chongqing University of Arts and Sciences, Chongqing 402160,China)

机构地区：[1]重庆文理学院电子电气工程学院,重庆402160

出　　处：《电子元件与材料》2017年第1期27-32,共6页Electronic Components And Materials

基　　金：国家自然科学基金资助(No.11574253);重庆市教育委员会科学技术研究项目(No.KJ1601118);重庆文理学院科技项目(No.Y2015DQ34)

摘　　要：考虑原子的短程相互作用和原子的非简谐振动,推导出石墨烯的声子平均自由程随温度变化的关系式,探讨了非简谐振动对它们的影响。结果表明:石墨烯的声子平均自由程随温度升高而非线性减小,温度低于20 K时,自由程随温度升高而急剧减小;温度高于300 K时,自由程随温度升高而减小的速度逐渐减慢;声子平均自由程随温度的变化率dl/dt均为负值,且随着温度升高而减小。在极低温条件下(T<20 K),自由程的温度变化率随温度升高而变化很大,此后,变化速度逐渐减慢;与简谐近似的值相比,非简谐项引起的声子平均自由程及其变化率的差值均随温度升高而增大。By considering the non-harmonic effect and short-range interaction of atoms, the current work obtained the analytic functions of the graphene's phonon mean free path depending on temperature, and the influence of anharmonic vibration on them was also investigated. The theoretical results indicate that the graphene's phonon mean free path decreases nonlinearly with the increase of temperature. When the temperature is below 20 K, the free path sharply decreaseswith the increase of temperature. And changes become gradually slow at the temperature above 300 K. All relative change rate (dl/dt) of phonon mean free path is negative and decreases with the increase of temperature. The change rate of the free path sharply decreases with the increase of temperature when temperatures is below 20 K, then the changes gradually slow down. Compared with the results of the harmonic approximation, the anharmonic effects on phonon mean free path and its change rate become more significant with temperature getting higher.

关 键 词：石墨烯 德拜温度 声子平均自由程 非简谐效应 原子短程作用 温度变化率 

分 类 号：TN604[电子电信—电路与系统]