Voltage-Induced Rearrangements in Atomic-Size Contacts.
Voltage-Induced Rearrangements in Atomic-Size Contacts.
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DOI：
10.1021/acs.nanolett.0c01597
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发表时间：
2020-06
期刊：
影响因子：
10.8
通讯作者：
Markus Ring;David J Weber;Patrick Haiber;F. Pauly;P. Nielaba;E. Scheer
中科院分区：
文献类型：
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作者：
Markus Ring;David J Weber;Patrick Haiber;F. Pauly;P. Nielaba;E. Scheer
研究了Pb、Au、Al、Cu原子接触的电压诱导电导变化。实验是在低温真空中进行的，使用机械可控的断开结。我们确定开关直方图，即开关电压和开关电流的分布函数，作为电导的函数。我们观察到一个明确的材料依赖性：Au揭示了最高的，几乎conductionanceindependent开关电压，而铝有一个明显的依赖于电导最低。理论研究采用密度泛函理论和广义朗之万方程考虑特定声子模式的泵浦。我们确定了一个失控的电压作为阈值，在该泵不稳定的原子排列。我们发现定性协议之间的平均开关电压和失控电压的材料和电导的依赖性和接触到接触的平均特征电压的变化，这表明声子泵浦是一个相关的机制驱动的实验接触中的重排。
We study voltage-induced conductance changes of Pb, Au, Al, Cu atomic contacts. The experiments are performed in vacuum at low temperature using mechanically controllable break junctions. We determine switching histograms, i.e. distribution functions of switching voltages and switching currents, as function of the conductance. We observe a clear material dependence: Au reveals the highest and almost conductanceindependent switching voltage, while Al has the lowest with a pronounced dependence on the conductance. The theoretical study uses density functional theory and a generalized Langevin equation considering the pumping of particular phonon modes. We identify a runaway voltage as the threshold at which the pumping destabilizes the atomic arrangement. We nd qualitative agreement between the average switching voltage and the runaway voltage regarding the material and conductance dependence and contact-to-contact variation of the average characteristic voltages, suggesting that the phonon pumping is a relevant mechanism driving the rearrangements in the experimental contacts.