Optically and electrically induced electron-spin transport in molecular systems

Exquisite control of spin-electron interactions at a molecular level is still elusive. It is however of great importance as it has the potential to affect the area of nanoelectronics as a whole, and the ongoing challenge for miniaturization in the Information technology industry. This fast-paced industry has already reached the nanoscale (a few-months ago IBM revealed a 5 nm chip). However, as researchers are reaching the single molecule level, more challenges arise.

This project aims at advancing knowledge in this sensitive area. It is a strongly multidisciplinary project, which makes use of a mix of chemical and physical methods to overcome present experimental limitations in our understanding of spin-electron interactions. We shall use chemical methods for the synthesis of magnetic molecules and the functionalization of endohedral fullerene species that carry optically active groups at several frequencies, including the commercially accessible optical frequency of 1.5 mu. The addition of photoactive groups on a molecule, affords the flow of electrons through or close to the adjacent spin centre after a light pulse. In addition, we shall place a magnetic molecule between bulk electrodes. This affords an ultra-clean system that can be studied in bulk, with a perfectly defined geometry of the magnetic and electronic elements. The results can then be compared to transport experiments at mK temperatures.

We shall use advanced methodologies for materials synthesis of well-defined molecules including isomerically pure species. We shall use advanced techniques for materials characterization such as UV-Vis spectroscopy, MALDI Mass Spectrometry and purification techniques such as high performance liquid chromatography (HPLC). In addition, we shall use electron paramagnetic resonance (EPR) techniques. We have access to CW EPR and to pulsed EPR with ns time resolution. We have access to an optical cavity coupled to magnetic fields. This will allow us to probe molecules with optically-active moieties (such as endohedral fullerenes containing Er ions) that see electron transfer activity under irradiation.

The project goes beyond the state-of-the-art. Firstly it combines, uniquely, molecular magnets with endohedral fullerenes. These hybrid materials are novel and allow the study of electron spin interactions with charge transfer processes. Secondly, we aim to do this at the single molecule level. If successful, our results will impact on several key technologies including spin-dependent transport (spintronics) and single-molecule electronics.

Hence the project aligns to several EPSRC areas such as:
- Information and communications technologies (ICT)
- Physical sciences
- Quantum technologies

The project involves a close collaboration between two groups in the Department of Materials, Oxford and brings together a synergy of chemical synthesis, optical spectroscopy and magnetic properties study. It blurs the borders between chemistry and physics and allows for cutting edge materials science research with nanotechnological implications.