Völklein F, Reith H, Cornelius T W, Rauber M, Neumann R
University of Applied Sciences Wiesbaden, Am Brückweg 26, D-65428 Rüsselsheim, Germany.
Nanotechnology. 2009 Aug 12;20(32):325706. doi: 10.1088/0957-4484/20/32/325706. Epub 2009 Jul 21.
A new method for the measurement of thermal conductivity of electrically conducting single nanowires is presented. First experimental investigations are focused on the thermal conductivity of metallic Pt nanowires with a diameter of (typically) 100 nm and a length of 10 microm. Thermal conductivity data are compared with measurements of electrical conductivity in order to test the Wiedemann-Franz law for metallic nanowires. Compared to the bulk values at room temperature, electrical and thermal conductivities of the nanowire are decreased by a factor of 2.5 and 3.4, respectively. Consequently, the Lorenz number L = lambda/sigmaT = 1.82 x 10(-8) V(2) K(-2) of the nanowire is smaller than the bulk Lorenz number L(bulk) = (pi(2)/3)(k/e)(2) = 2.44 x 10(-8) V(2) K(-2) of metals. Furthermore, the temperature coefficient beta of electrical resistivity is also reduced compared to the bulk value. These decreases of lambda, sigma and beta can be attributed to size effects, mainly caused by grain boundary scattering of electrons.
本文提出了一种测量导电单纳米线热导率的新方法。首次实验研究聚焦于直径（通常）为100纳米、长度为10微米的金属铂纳米线的热导率。将热导率数据与电导率测量值进行比较，以检验金属纳米线的维德曼-夫兰兹定律。与室温下的体材料值相比，纳米线的电导率和热导率分别降低了2.5倍和3.4倍。因此，纳米线的洛伦兹数L = λ/σT = 1.82×10⁻⁸ V² K⁻² 小于金属的体材料洛伦兹数L(bulk) = (π²/3)(k/e)² = 2.44×10⁻⁸ V² K⁻² 。此外，与体材料值相比，电阻率的温度系数β也降低了。λ、σ和β的这些降低可归因于尺寸效应，主要是由电子的晶界散射引起的。
