Engineering Magnetic Hybridization at Organic–Ferromagnetic Interfaces by C60-Adsorption-Induced Fe(001) Surface Reconstruction

• Published in: Journal of physical chemistry. C
• Main Authors: Yang, Zhen-Hua, Pang, Rui, Shi, Xing-Qiang
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.05.2015
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.5b03954

Large magnetoresistance has been reported for C60-based vertical spin valves. But for the underlying organic–ferromagnetic interfacial atomistic structures, both experimental and theoretical works have assumed unreconstructed atomic structures for the magnetic surfaces, although organic molecule (e.g., fullerene and thiolate) adsorption frequently induces nonmagnetic surfaces reconstruction. Here we report that C60 adsorption can induce a prototype ferromagnetic surface, Fe(001), reconstruction, via thorough structural search from first-principles calculations. We propose that Fe(001) surface reconstruction should already occur under the reported annealing temperature in literature. Reconstruction solidifies C60/Fe interface bonding and enhances C60 spin-polarization. More importantly, only our reconstructed structure can explain the experimental observation of an inversion of C60 spin-polarization around Fermi-level relative to that of Fe substrate, which is attributed to the C60 lowest unoccupied molecular orbitals LUMO-derived states are shifted to Fermi level by charge transfer and to the strong coupling in the reconstructed structure. One could expect that surface reconstruction occur not only at the C60/Fe­(001) interface, but also at interfaces of other molecule-magnetic metals. Hence our work offers a new pathway to interface engineering, that is, via surface reconstruction to manipulate spintronic properties and promote the field of interface-assisted spintronics.