Promises and Challenges of Organic Spintronics 

Dr. Christopn Boehme

Department of Physics and Astronomy
University of Utah


While the term “Spintronics" was originally introduced as label for technologies that represent information through spin states rather than charge states, it is nowadays oftentimes used solely in the context of spin-polarization, spin-injection, and spin-transport effects for which spin-orbit interaction plays an important role. Silicon and carbon based semiconductors display only weak spin-orbit coupling and - in the case of organic semiconductors - charge transport via hopping through strongly localized states. These materials appear at first glance therefore to be entirely unsuitable for spintronics. However, they also exhibit spin related effects not seen in materials with strong spin-orbit coupling which can be used for alternative, different approaches to spintronics based on spin-permutation symmetry states of charge carrier pairs rather than spin-polarization states. Reading spin-permutation symmetry is straight forward when pronounced spin-selection rules exist1,2. In contrast to spin-polarization, permutation symmetry does not depend directly on temperature and magnetic field strength3. Furthermore, the absence of spin-orbit coupling can also allow for long spin-coherence times and thus, the possibility to connect spintronics to an all spin based memory which may be applicable to spin-based quantum information4 concepts and for similar reasons, it allows for magnetic resonance based spin-manipulation schemes. Crucial for the successful implementation of organic spintronics will be a fundamental understanding of the microscopic electronic processes which are aimed to be utilized for this new technology, a requirement which has only partially achieved. Developing this understanding will be among the most important challenges of this field5. In this talk, our work on the development of this organic spintronics will be presented and the issues at hand as well as the progress made will be discussed.

 

[1]       D. R. McCamey, H. A. Seipel, S. Y. Paik, M. J. Walter, N. J. Borys, J. M. Lupton, and C. Boehme, Nature Materials, 7, 723 (2008).

[2]       D. R. McCamey, K. J. van Schooten, W. J. Baker, S.-Y. Lee, S.-Y. Paik, J. M. Lupton, and C. Boehme, Phys. Rev. Lett. 104, 017601 (2010).

[3]       W. J. Baker, K. Ambal, D. P. Waters, R. Baarda, H. Morishita, K. van Schooten, D. R. McCamey, J. M. Lupton, and C. Boehme, Nature Commun. 3, 898 (2012).

[4]       W. J. Baker, T. L. Keevers, J. M. Lupton. D. R. McCamey, and C. Boehme,  Phys. Rev. Lett. 108, 267601 (2012).

[5]       C. Boehme and J. M. Lupton, Nature Nano. 8, 612 (2013).