| AVS 58th Annual International Symposium and Exhibition | |
| Graphene and Related Materials Focus Topic | Tuesday Sessions |
| Session GR+MI-TuA |
| Session: | Graphene: Magnetic Properties and Spin-Dependent Phenomena |
| Presenter: | Andreas Sandin, North Carolina State University |
| Authors: | A.A. Sandin, North Carolina State University D.B. Dougherty, North Carolina State University J.E. Rowe, North Carolina State University |
| Correspondent: | Click to Email |
Graphene may be an ideal material for spin field effect transistors because of its high charge carrier mobility and long spin relaxation times due to small spin-orbit coupling.1 However, efficient spin injection into graphene requires overcoming conductivity mismatch through the use of tunnel barriers and/or spin filters.2 It is possible that organic films can serve as tunnel barriers/spin filters with highly tailorable properties. In particular, metal phthalocyanines have recently been shown to exhibit spin dependent interfacial coupling on magnetic electrodes.3 A study of the coupling and morphology of such molecules on graphene is a crucial first step to understand potential spin enhanced interfaces.
We deposit monolayer iron phthalocyanine (FePc) on both single layer and bilayer epitaxial graphene on the Si-terminated polar face of SiC, named SiC(0001). Scanning tunneling microscopy reveals an adsorbed molecular lattice periodicity of 1.8 nm, close to that of the graphene/SiC buffer layer corrugation periodicity. This lattice spacing is larger than that of FePc adsorbed on a graphite surface that shows a smaller spacing of ~1.4 nm. This implies a stronger interaction of the FePc with epitaxial graphene than expected and is possibly due to the modification of graphene by the SiC substrate. Tunneling spectroscopy has been used to study the occupied and unoccupied electronic states of the absorbed monolayer FePc. Broad unoccupied states indicate significant electronic coupling between the molecules and the graphene and suggest a promising future for molecular strategies for spin injection.
*Supported by the NSF Center for Chemical Innovation: Center for Molecular Spintronics under CHE-0943975.
1. Y. G. Semenov, K. W. Kim and J. M. Zavada, Appl. Phys. Lett. 91 (15), 3 (2007).
2. W. Han, K. Pi, K. M. McCreary, Y. Li, J. J. I. Wong, A. G. Swartz and R. K. Kawakami, Phys. Rev. Lett. 105 (16), 4 (2010).
3. C. Iacovita, M. V. Rastei, B. W. Heinrich, T. Brumme, J. Kortus, L. Limot and J. P. Bucher, Physical Review Letters 101 (11), 116602-116604 (2008).