物理学报2017，Vol.66Issue(22)：213-221,9.DOI:10.7498/aps.66.224701
石墨烯低温热膨胀和声子弛豫时间随温度的变化规律
Variation of thermal expansion at low temperature and phonon relaxation time in graphene with temperature
摘要
Abstract
Considering the anharmonic vibrations and the interactions between electron and phonon of atoms,in this article we study the temperature dependence of Grüneisen parameter,thermal expansion coefficient at low temperature and phonon relaxation time by using the theory and method of solid state physics.The influences of the anharmonic vibration of the atom on the above parameters are further discussed.The obtained results are as follows.1) The thermal expansion coefficient of graphene is a negative value when the temperature drops below room temperature.The absolute value of the thermal expansion coefficient of graphene increases monotonically with the increase of temperature.The thermal expansion coefficient of graphene is-3.64 × 10-6 K-1 at room temperature.2) The value of Griineisen parameter is zero in the harmonic approximation.If the anharmonic vibration is considered,the Griineisen parameter will increase slowly with the increase of temperature.Its value is between 1.40 and1.42 and the change is almost linear.And we find that the influence of the second anharmonic term is less than that of the first anharmonic term on Grüneisen parameter.3) The phonon relaxation time decreases with the increase of temperature.The rate changes rapidly at low temperature (T ＜ 10 K),then it changes very slowly.The phonon relaxation time is almost inversely proportional to temperature when the temperature is higher than 300 K.关键词
石墨烯/低温热膨胀系数/格林艾森参量/弛豫时间Key words
graphene/thermal expansion coefficient at low temperature/Grüneisen parameter/relaxation time引用本文复制引用
任晓霞,申凤娟,林歆悠,郑瑞伦..石墨烯低温热膨胀和声子弛豫时间随温度的变化规律[J].物理学报,2017,66(22):213-221,9.基金项目
Project supported by the National Natural Science Foundation of China (Grant No.51505086),The Scientific and Technological Research Program of Chongqing Municipal Education Commission,China (Grant Nos.KJ1601118,KJ1601111),and the Natural Science Foundation Project of Chongqing (CSTC),China (Grant No.Cstc2015jcyjA40054).国家自然科学基金(批准号:51505086)、重庆市教委科技项目(批准号:KJ1601118,KJ1601111)和重庆市基础与前沿研究项目(批准号:cstc2015jcyjA40054)资助的课题. （Grant No.51505086）
