Influence of grain boundary scattering on the electrical and thermal conductivities of polycrystalline gold nanofilms
Influence of grain boundary scattering on the electrical and thermal conductivities of polycrystalline gold nanofilms
复制标题
晶界散射对多晶金纳米薄膜电导率和导热率的影响
DOI：
10.1103/physrevb.74.134109
复制
发表时间：
2006-10-01
影响因子：
3.7
通讯作者：
Takahashi, K.
中科院分区：
文献类型：
--
作者：
Zhang, Q. G.;Cao, B. Y.;Takahashi, K.
采用直流加热法同时测量了多晶金纳米膜的电导率和导热系数，并将测量结果与Mayadas和Shatzkes理论进行了比较。研究发现，金纳米膜的电导率和热导率的降低主要受晶界散射的影响。电荷输运过程中电子撞击晶界的反射系数为0.7，与先前扫描隧穿电位法的研究结果吻合较好。而热输运的反射系数只有0.25。多晶金纳米膜的洛伦兹数，是由测量的电导率和导热率计算出来的，远远大于Wiedemann-Franz定律对块状材料的预测值。结果表明，晶界上的电子散射对多晶金纳米膜的电荷输运和热输运有不同的影响。利用传导电子的有效密度模型解释了多晶金纳米膜中Wiedemann-Franz定律的违反。
The electrical and thermal conductivities of polycrystalline gold nanofilms have been measured simultaneously by a direct current heating method, and the measured results are compared with the Mayadas and Shatzkes theory. It is found that the reduced electrical and thermal conductivities of gold nanofilms are strongly dominated by grain boundary scattering. The reflection coefficient of electrons striking the grain boundaries for charge transport is 0.7, which agrees well with a previous scanning tunneling potentiometry study. The reflection coefficient for thermal transport, however, is only 0.25. The Lorenz numbers for the polycrystalline gold nanofilms, which are calculated from the measured electrical and thermal conductivities, are much greater than the value predicted by the Wiedemann-Franz law for the bulk material. The results indicate that the electron scatterings on the grain boundaries impose different influences on the charge and heat transport in the polycrystalline gold nanofilms. A model of effective density of conduction electrons has been utilized to interpret the violation of the Wiedemann-Franz law in polycrystalline gold nanofilms.