Molecules for spin electronics – MOSE

This research combines molecular electronics and spin electronics by studying electric transport properties of molecule(s) connecting two magnetic electrodes. The planned experiments intend to: - fabricate magnetic electrodes separated by 1-2 nm, with optimized mechanical stability properties. The method will combine lithography techniques with electrochemistry, allowing control of the surface chemistry of the electrodes. - synthesize original molecules, with binding termination sites optimized for magnetic electrodes, giving access to properties described below - synthesize metal-metal bonded molecular wires connecting two magnetic electrodes, using electrochemical methods, ideally compatible with the fabrication method for the electrodes - search for large magnetoresistance effects, involving a change of conduction properties under change of the mutual orientation of the two electrodes, - implement a microsphere method for molecular bridging of larger systems, providing an alternative solution to the challenging task of making very close electrodes. This experiment will also provide a platform for properties comparison between ensemble of molecules and single molecule electric transport. - validate the hypothesis of conduction through a single molecule by fluorescence signal detection. The electrochemical cell will be integrated in an optical setup providing illumination under total reflection conditions, ideal for detecting single molecules fluorescence at low concentrations - validate the hypothesis of conductions through a single molecule through resonance effects in tunnel magnetoresistance properties, taking advantage of molecules with asymmetrical density of states - use an electrostatic and/or electrochemical gate control giving access to other molecular electronic states, resulting in changes of magnetoresistance properties - perform measurements under visible light excitation, for the purpose of promoting electronic transitions of long decay time. We will be interested in particular in photomagnetic molecules. This ambitious project will be highly interdisciplinary. It will assemble several complementary chemical and electrochemical synthesis laboratories around a newly created physics laboratory studying spintronics at the nanometer scale. This latter one is funded though a Chaire d'excellence fellowship, providing significant resources for making the electrodes structures and starting the physics studies. The requested funding aims at boosting the interdisciplinary side of the project, providing the grounds for new collaborative research. During the last two years, theoretical predictions of enhanced magnetoresistance properties at the molecular scale, first identification of the best binding terminations on ferromagnetic surfaces, and resonant tunneling effects in magnetic systems, have been found. This project remains high-risk, but the involved laboratories demonstrated the capability of fabricating the two parts (electrodes and molecules) necessary to succeed in this project. This grant will provide resources for combining the expertises, at ideal timing where all key steps of this project have been recently validated, with a perspective of new fundamental discoveries having an impact for the future of ultra-miniaturized electronics.