Actuated Transitory Metal−Ligand Bond As Tunable Electromechanical Switch

详细信息    查看全文

• 作者：Robin Ohmann ; Lucia Vitali ; Klaus Kern
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：August 11, 2010
• 年：2010
• 卷：10
• 期：8
• 页码：2995-3000
• 全文大小：487K
• 年卷期：v.10,no.8(August 11, 2010)
• ISSN：1530-6992

文摘

Electrically tunable molecules are highly attractive for the construction of molecular devices, such as switches, transistors, or machines. Here, we present a novel nanomechanical element triggered by an electrical bias as external stimulus. We demonstrate that a transitory chemical bond between a copper atom and coordinating organic molecules adsorbed on a metal surface acts as variable frequency switch, which can be actuated and probed by means of low-temperature scanning tunneling microscopy. Whereas below a threshold bias voltage the bond is permanently either formed or broken the bonding state continuously oscillates at higher voltages. The switching rate of the bistable molecular system can be widely tuned from below 1 Hz up to the kilohertz regime. The quantum yield per tunneling electron to trigger a transition between the two states varies spatially and is related to the local density of states of the bonded and nonbonded configuration.

Keywords:

Conductance switching; metal−ligand bond; nanoelectromechanical systems; time-resolved spectroscopy; electron quantum yield; scanning tunneling microscopy