Molecules for Spin Devices

Molecular electronics [1] aims to use molecules as building blocks for the fabrication of electronic components—diodes, switches, transistors, and the like. At the heart of this idea is the possibility of synthesizing organic molecules with tailored properties, manipulating their electronic structure and optimizing their binding to different surfaces. Devices as small as a few molecules might lead to substantial size reduction in electronics, providing a possible solution for extending Moore’s law beyond the anticipated limits of conventional integrated circuits [2]. Molecular electronics may also be inspired by developments in modern solid-state spintronics: instead of using the electron charge for manipulating and storing information, one might find it a natural extension to focus on the spin degree of freedom as the ultimate carrier of information. In what has been dubbed “molecular spintronics” [3], the seemingly distinct fields of molecular electronics and spintronics come together. Now, in an article in Physical Review Letters, Martin Callsen and colleagues from the Forschungszentrum Jülich in Germany present theoretical simulations that suggest a new approach for designing molecular spintronics devices [4]. The theorized devices would be suitable to build molecular memory units or spin filters—devices that preferentially transmit electrons with a certain spin orientation.