College of Water Resources and Architectural Engineering, Northwest A&F University, 712100 Yangling, P.R. China.
Institute of Structural Mechanics, Bauhaus-University Weimar, 99423 Weimar, Germany.
Sci Rep. 2017 Jan 25;7:41398. doi: 10.1038/srep41398.
Tensile strain and compress strain can greatly affect the thermal conductivity of graphene nanoribbons (GNRs). However, the effect of GNRs under shear strain, which is also one of the main strain effect, has not been studied systematically yet. In this work, we employ reverse nonequilibrium molecular dynamics (RNEMD) to the systematical study of the thermal conductivity of GNRs (with model size of 4 nm × 15 nm) under the shear strain. Our studies show that the thermal conductivity of GNRs is not sensitive to the shear strain, and the thermal conductivity decreases only 12-16% before the pristine structure is broken. Furthermore, the phonon frequency and the change of the micro-structure of GNRs, such as band angel and bond length, are analyzed to explore the tendency of thermal conductivity. The results show that the main influence of shear strain is on the in-plane phonon density of states (PDOS), whose G band (higher frequency peaks) moved to the low frequency, thus the thermal conductivity is decreased. The unique thermal properties of GNRs under shear strains suggest their great potentials for graphene nanodevices and great potentials in the thermal managements and thermoelectric applications.
拉伸应变和压缩应变会极大地影响石墨烯纳米带(GNRs)的导热系数。然而,剪切应变对 GNRs 的影响(也是主要应变影响之一)尚未得到系统的研究。在这项工作中,我们采用反向非平衡分子动力学(RNEMD)对剪切应变下 GNRs(模型尺寸为 4nm×15nm)的导热系数进行了系统的研究。我们的研究表明,GNRs 的导热系数对剪切应变不敏感,在原始结构断裂之前,导热系数仅下降 12-16%。此外,我们还分析了声子频率和 GNRs 微结构的变化,如能带角和键长,以探讨导热系数的变化趋势。结果表明,剪切应变的主要影响是在面内声子态密度(PDOS)上,其 G 带(高频峰)向低频移动,从而导致导热系数降低。GNRs 在剪切应变下的独特热性能表明,它们在石墨烯纳米器件中有很大的应用潜力,在热管理和热电应用中也有很大的应用潜力。