A current-driven single-atom memory

• Published in: Nature nanotechnology Vol. 8; no. 9; pp. 645 - 648
• Main Authors: Schirm, C., Matt, M., Pauly, F., Cuevas, J. C., Nielaba, P., Scheer, E.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.09.2013; Nature Publishing Group
• Subjects: 639/925/927/1007; Aluminum; Conductance; Contact; Devices; Electronics; Electrons; Hysteresis; Information storage; letter; Materials Science; Nanotechnology; Nanotechnology and Microengineering; Switches; Transistors; Germany
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/nnano.2013.170

The possibility of fabricating electronic devices with functional building blocks of atomic size is a major driving force of nanotechnology 1 . The key elements in electronic circuits are switches, usually realized by transistors, which can be configured to perform memory operations. Electronic switches have been miniaturized all the way down to the atomic scale 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 . However, at such scales, three-terminal devices are technically challenging to implement. Here we show that a metallic atomic-scale contact can be operated as a reliable and fatigue-resistant two-terminal switch. We apply a careful electromigration protocol to toggle the conductance of an aluminium atomic contact between two well-defined values in the range of a few conductance quanta. Using the nonlinearities of the current–voltage characteristics caused by superconductivity 10 in combination with molecular dynamics and quantum transport calculations, we provide evidence that the switching process is caused by the reversible rearrangement of single atoms. Owing to its hysteretic behaviour with two distinct states, this two-terminal switch can be used as a non-volatile information storage element. Electromigration is used to rearrange single atoms in an atomic-sized metal contact and to switch its conductance between two well-defined values, enabling memory device functionality.