AC stability of metal single-atom contacts

2016 Fiscal Year Final Research Report

• Project/Area Number: 26390028
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Nanomaterials engineering
• Research Institution: Kyoto University
• Principal Investigator: Sakai Akira 京都大学, 工学研究科, 教授 (80143543)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 金属単原子接点 / 接点安定性 / 交流安定性 / エレクトロマイグレーション

Outline of Final Research Achievements

Metal contacts generally show better high-bias stability under AC biases because of the time-averaging of the electromigration force under alternating currents. To observe this AC effect for single-atom contacts of metals, we carried out break-voltage and lifetime measurements on Au single-atom contacts under AC biases. For frequencies up to 100 kHz, the AC break voltage does not surpass the one at DC. The absence of the AC effect can be understood by considering the hopping of electrode atoms, the frequency of which increases with the bias and makes the time averaging of the electromigration force ineffective near the breakdown. Thus, we employed a low bias and measured the contact lifetime at 1 MHz. However, the lifetime distributions obtained at DC and 1 MHz appear the same and show no signs of the AC effect. Probably, the electromigration force is not a dominant instability mechanism at low biases and its reduction by the AC effect little affects the contact lifetime.

Free Research Field

ナノ構造物理