Local heating in nanoscale conductors
Local heating in nanoscale conductors
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DOI：
10.1021/nl0348544
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发表时间：
2003-12-01
期刊：
影响因子：
10.8
通讯作者：
Di Ventra, M
中科院分区：
文献类型：
--
作者：
Chen, YC;Zwolak, M;Di Ventra, M
我们报告的第一性原理计算的局部加热纳米结形成的一个单一的分子和一个黄金点接触。由于较低的电流密度和较大的热耗散，单分子比金点接触发热少。我们还发现，在零温度下，阈值偏置V-开始约为6 mV和11 mV的分子和点接触，分别需要激发最小的振动模式，并产生热量。后者的估计是在同一系统上最近的实验结果非常吻合。在给定的外部偏压V低于V-onset时，当背景温度约为e（V-onset - V）/k（B）时，加热变得明显。在V-起始以上，局部加热随着偏压的增加而急剧增加，这主要是由于纵向模式的激发，但也通过热耗散到电极中而被显著抑制，只要纳米结构和体电极之间存在良好的热接触。
We report first-principles calculations of local heating in nanoscale junctions formed by a single molecule and a gold point contact. Due to the lower current density and larger heat dissipation, the single molecule heats less than the gold point contact. We also find that, at zero temperature, threshold biases V-onset of about 6 mV and 11 mV for the molecule and the point contact, respectively, are required to excite the smallest vibrational mode and generate heat. The latter estimate is in very good agreement with recent experimental results on the same system. At a given external bias V below V-onset, heating becomes noticeable when the background temperature is on the order of approximately e(V-onset - V)/k(B). Above V-onset, local heating increases dramatically with increasing bias, mainly due to excitation of longitudinal modes, but is also considerably suppressed by thermal dissipation into the electrodes, provided good thermal contacts exist between the nanostructure and the bulk electrodes.