Miao Tingting, Li Dawei, Shi Shaoyi, Ji Zhongli, Ma Weigang, Zhang Xing, Zhong Qing, Wang Xueshen
Beijing Key Laboratory of Process Fluid Filtration and Separation, College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing Beijing 102249 China.
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics, Tsinghua University Beijing 100084 China
RSC Adv. 2018 Jun 6;8(37):20679-20685. doi: 10.1039/c8ra01699b. eCollection 2018 Jun 5.
The electrical resistivity of suspended polycrystalline gold nanofilms with different lengths has been measured over the temperature range of 2 K to 340 K, which dramatically increases compared with bulk gold and slightly increases with length. Classical size effect theories considering surface and grain boundary scatterings cannot explain the increased film resistivity, especially the temperature dependence of resistivity, over the whole temperature range. Considering the fact that the reduction of the coordination number of atoms at the surface and the interface leads to a decrease of the phonon spectrum frequency and consequently affects the surface phonon spectrum, the electron-phonon interaction as a relatively independent surface effect is taken into account. The theoretical predictions and the experimental measured film resistivity match very well over the whole temperature range and the extracted surface Debye temperature decreases significantly compared to the bulk value, which illustrates the essential role of enhanced surface electron-phonon interactions on the electrical transport of the present gold nanofilms.
在2 K至340 K的温度范围内，测量了不同长度的悬浮多晶金纳米薄膜的电阻率。与块状金相比，其电阻率显著增加，且随长度略有增加。考虑表面和晶界散射的经典尺寸效应理论无法解释整个温度范围内薄膜电阻率的增加，尤其是电阻率的温度依赖性。考虑到表面和界面处原子配位数的减少会导致声子谱频率降低，进而影响表面声子谱，将电子 - 声子相互作用作为一种相对独立的表面效应加以考虑。理论预测与实验测量的薄膜电阻率在整个温度范围内匹配得非常好，并且提取的表面德拜温度与块状值相比显著降低，这说明了增强的表面电子 - 声子相互作用对当前金纳米薄膜电输运的重要作用。
