Symmetry-selected spin-split hybrid states in C$_{60}$ / ferromagnetic interfaces

Dongzhe Li (1) , Cyrille Barreteau (1) , Seiji Leo Kawahara (2) , Jérôme Lagoute (2) , Cyril Chacon (2) , Yann Girard (2) , Sylvie Rousset (2) , Vincent Repain (2) , Alexander Smogunov (1)

1 GMT - Groupe Modélisation et Théorie
2 MPQ (UMR_7162) - Laboratoire Matériaux et Phénomènes Quantiques

The understanding of orbital hybridization and spin-polarization at the organic-ferromagnetic interface is essential in the search for efficient hybrid spintronic devices. Here, using first-principles calculations, we report a systematic study of spin-split hybrid states of C$_{60}$ deposited on various ferromagnetic surfaces: bcc-Cr(001), bcc-Fe(001), bcc-Co(001), fcc-Co(001) and hcp-Co(0001). We show that the adsorption geometry of the molecule with respect to the surface crystallographic orientation of the magnetic substrate as well as the strength of the interaction play a crucial role in the spin-polarization of the hybrid orbitals. We find that a large spin-polarization in vacuum above the buckyball can only be achieved if the molecule is adsorbed upon a bcc-(001) surface by its pentagonal ring. Therefore, bcc-Cr(001), bcc-Fe(001) and bcc-Co(001) are the optimal candidates. Spin-polarized scanning tunneling spectroscopy measurements on single C$_{60}$ adsorbed on Cr(001) and Co/Pt(111) also confirm that both the symmetry of the substrate and of the molecular conformation have a strong influence on the induced spin polarization. Our finding may give valuable insights for further engineering of spin filtering devices through single molecular orbitals.

Domains: Physics [physics]

Dongzhe Li, Cyrille Barreteau, Seiji Leo Kawahara, Jérôme Lagoute, Cyril Chacon, et al.. Symmetry-selected spin-split hybrid states in C$_{60}$ / ferromagnetic interfaces. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2016, 93, pp.085425. ⟨10.1103/PhysRevB.93.085425⟩. ⟨cea-01481437⟩