The Chemical Structure, Dynamics and Mechanism B (CSDM-B) program supports Professor Michael R. Wasielewski of Northwestern University to carry out fundamental studies on controlling the spin dynamics of complex multi-spin molecular systems that target spintronics and quantum information processing. Fast photo-initiated electron transfer within covalently-linked organic donor-acceptor molecules having specific donor-acceptor (D-A) distances and orientations results in the formation of spin-entangled electron-hole pairs (i.e. spin-correlated radical ion pairs, SCRPs) having well-defined initial spin configurations and magnetic spin-spin interactions. The project focuses on the demanding task of controlling spin coherence within organic molecular arrays using SCRPs in tailored covalent structures. The specific goals are to investigate: 1) What is the scope of spin coherence transfer by optical excitation of an SCRP? 2) What factors determine coherence dephasing in SCRPs? 3) Can coherent spin states be transported ("teleported") over long distances using SCRPs? 4) Can nuclear spins be used to store and retrieve coherent electron spin states produced by an SCRP?
Developing a fundamental understanding of how to control charge and spin transport through organized arrays of organic molecules is critical to the development of new electronics and spintronics especially with regard to their potential impact on computers and information processing. Taking advantage of the quantum nature of electron spin may lead to advanced computer technologies with broad applications throughout society. The use of organic materials and bio-inspired approaches to these problems offers the possibility of developing solutions that are not only versatile, but are cost effective and environmentally benign as well.
