Isshiki Yuji, Li Dongzhe, Kiguchi Manabu, Nishino Tomoaki, Pauly Fabian, Fujii Shintaro
Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1 W4-10 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
CEMES, Université de Toulouse, CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse, France.
ACS Appl Mater Interfaces. 2022 Mar 9;14(9):11919-11926. doi: 10.1021/acsami.1c24096. Epub 2022 Feb 28.
The complex behavior of the simplest atomic-scale conductors indicates that the electrode structure itself is significant in the design of future nanoscale devices. In this study, the structural asymmetry of metallic atomic contacts formed between two macroscopic Au electrodes at room temperature was investigated. Characteristic signatures of the structural asymmetries were detected by fast current-voltage (-) measurements with a time resolution of approximately 100 μs. Statistical analysis of more than 300,000 - curves obtained from more than 1000 contact-stretching processes demonstrates that the current rectification properties are correlated with the conductance of the nanocontacts. A substantial suppression of the variation in current rectification was observed for the atomic contacts with integer multiples of the conductance quantum. Statistical analysis of the time-resolved - curves revealed that the current rectification variations increased significantly from 500 μs onward before the breakage of the atomic contacts. Ab initio atomistic simulations of the stretching processes and corresponding - characteristics confirmed the magnitude of the rectification and related it to the structural asymmetries in the breakdown process of the junctions. Overall, we provide a better understanding of the interplay between geometric and electronic structures at atomically defined metal-metal interfaces by probing charge transport properties in extremely sensitive nanocontacts.
最简单的原子尺度导体的复杂行为表明，电极结构本身在未来纳米尺度器件的设计中具有重要意义。在本研究中，对室温下两个宏观金电极之间形成的金属原子接触的结构不对称性进行了研究。通过时间分辨率约为100 μs的快速电流-电压（I-V）测量检测到了结构不对称性的特征信号。对从1000多个接触拉伸过程中获得的30多万条I-V曲线进行统计分析表明，电流整流特性与纳米接触的电导相关。对于具有电导量子整数倍的原子接触，观察到电流整流变化的显著抑制。对时间分辨I-V曲线的统计分析表明，在原子接触断裂之前，从500 μs起电流整流变化显著增加。对拉伸过程和相应I-V特性的从头算原子模拟证实了整流的幅度，并将其与结击穿过程中的结构不对称性相关联。总体而言，我们通过探测极其敏感的纳米接触中的电荷传输特性，更好地理解了原子定义的金属-金属界面处几何结构和电子结构之间的相互作用。
