Controlling the dynamics of spins on surfaces is pivotal to the design of spintronic1 and quantum computing2 devices. Proposed schemes involve the interaction of spins with graphene to enable surface-state spintronics3,4 and electrical spin manipulation4,5,6,7,8,9,10,11. However, the influence of the graphene environment on the spin systems has yet to be unravelled12. Here we explore the spin–graphene interaction by studying the classical and quantum dynamics of molecular magnets13 on graphene. Whereas the static spin response remains unaltered, the quantum spin dynamics and associated selection rules are profoundly modulated. The couplings to graphene phonons, to other spins, and to Dirac fermions are quantified using a newly developed model. Coupling to Dirac electrons introduces a dominant quantum relaxation channel that, by driving the spins over Villain’s threshold, gives rise to fully coherent, resonant spin tunnelling. Our findings provide fundamental insight into the interaction between spins and graphene, establishing the basis for electrical spin manipulation in graphene nanodevices.
This is a preview of subscription content, access via your institution
Open Access articles citing this article.
Scientific Reports Open Access 10 October 2019
Nature Communications Open Access 12 December 2016
Subscribe to Journal
Get full journal access for 1 year
only $9.92 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
Sanvito, S. Organic spintronics: Filtering spins with molecules. Nature Mater. 10, 484–485 (2011).
DiVincenzo, D. P. Quantum computation. Science 270, 255–261 (1995).
Pesin, D. & MacDonald, A. H. Spintronics and pseudospintronics in graphene and topological insulators. Nature Mater. 11, 409–416 (2012).
Han, W., Kawakami, R. K., Gmitra, M. & Fabian, M. Graphene spintronics. Nature Nanotech. 9, 794–807 (2014).
Garnica, M. et al. Long-range magnetic order in a purely organic 2D layer adsorbed on epitaxial graphene. Nature Phys. 9, 368–374 (2013).
Nair, R. R. et al. Dual origin of defect magnetism in graphene and its reversible switching by molecular doping. Nature Commun. 4, 2010 (2013).
Chen, J. J.-H., Li, L., Cullen, W. G. W., Williams, E. D. E. & Fuhrer, M. S. Tunable Kondo effect in graphene with defects. Nature Phys. 7, 535–538 (2011).
Nair, R. R. et al. Spin-half paramagnetism in graphene induced by point defects. Nature Phys. 8, 199–202 (2012).
Tombros, N., Jozsa, C., Popinciuc, M., Jonkman, H. T. & van Wees, B. J. Electronic spin transport and spin precession in single graphene layers at room temperature. Nature 448, 571–574 (2007).
McCreary, K. M., Swartz, A. G., Han, W., Fabian, J. & Kawakami, R. J. Magnetic moment formation in graphene detected by scattering of pure spin currents. Phys. Rev. Lett. 109, 186604 (2012).
Dlubak, B. et al. Highly efficient spin transport in epitaxial graphene on SiC. Nature Phys. 8, 557–561 (2012).
Cervetti, C., Heintze, E. & Bogani, L. Interweaving spins with their environment: Novel inorganic nanohybrids with controllable magnetic properties. Dalton Trans. 43, 4220–4232 (2014).
Gatteschi, D., Sessoli, R. & Villain, J. Molecular Nanomagnets (Oxford Univ. Press, 2006).
Hueso, L. E. et al. Transformation of spin information into large electrical signals using carbon nanotubes. Nature 445, 410–413 (2007).
Laird, E. A., Pei, F. & Kouwenhoven, L. P. A valley-spin qubit in a carbon nanotube. Nature Nanotech. 8, 565–568 (2013).
Kuemmeth, F., Ilani, S., Ralph, D. C. & McEuen, P. L. Coupling of spin and orbital motion of electrons in carbon nanotubes. Nature 452, 448–452 (2008).
Warner, M. et al. Potential for spin-based information processing in a thin-film molecular semiconductor. Nature 503, 504–508 (2013).
Oberg, J. C. et al. Control of single-spin magnetic anisotropy by exchange coupling. Nature Nanotech. 9, 64–68 (2014).
Mannini, M. et al. Quantum tunneling of the magnetization in a monolayer of oriented single-molecule magnets. Nature 468, 417–421 (2010).
Bogani, L. et al. Single-molecule-magnets carbon-nanotube hybrids. Angew. Chem. Int. Ed. 121, 760–764 (2009).
Ferrari, A. C. & Basko, D. M. Raman spectroscopy as a versatile tool for studying the properties of graphene. Nature Nanotech. 8, 235–246 (2013).
Misra, S. K., Poole, C. P. & Farach, H. A. A review of spin Hamiltonian forms for various point-group site symmetries. Appl. Magn. Reson. 11, 29–46 (1996).
Verniani, L. et al. Magnetic bistability of isolated giant-spin centers in a diamagnetic crystalline matrix. Chem. Eur. J. 18, 3390–3398 (2012).
Repollés, A., Cornia, A. & Luis, F. Spin-lattice relaxation via quantum tunneling in diluted crystals of Fe4 single-molecule magnets. Phys. Rev. B 89, 054429 (2014).
Koshino, M., Arimura, Y. & Ando, T. Magnetic field screening and mirroring in graphene. Phys. Rev. Lett. 102, 177203 (2009).
Fort, A., Rettori, A., Villain, J., Gatteschi, D. & Sessoli, R. Mixed quantum-thermal relaxation in Mn12 acetate molecules. Phys. Rev. Lett. 80, 612–615 (1998).
Leuenberger, M. N. & Loss, D. Spin tunneling and phonon-assisted relaxation in Mn12-acetate. Phys. Rev. B 61, 1286–1302 (2000).
Trauzettel, B., Bulaev, D. V., Loss, D. & Burkard, G. Spin qubits in graphene quantum dots. Nature Phys. 3, 192–196 (2007).
Lundberg, M. B., Yang, R., Renard, J. & Folk, J. A. Defect-mediated spin relaxation and dephasing in graphene. Phys. Rev. Lett. 110, 156601 (2013).
Yamamoto, M. et al. Electrical control of a solid-state flying qubit. Nature Nanotech. 7, 247–251 (2012).
We thank J. Wrachtrup and E. Rastelli for discussions; M. Konuma, U. Stützel, J. Sesé, A. L. Barra, D. Drung, Th. Schurig and L. Sebeke for assistance with the measurements; and financial support from Italian MIUR, Spanish MINECO (MAT2012-38318-C03-01), BW-Stiftung (Kompetenznetz Funktionelle Nanostrukturen), ERC-StG-338258 ‘OptoQMol’, the Royal Society (URF fellowship and grant) and the AvH Stiftung (Sofja Kovalevskaja award).
The authors declare no competing financial interests.
About this article
Cite this article
Cervetti, C., Rettori, A., Pini, M. et al. The classical and quantum dynamics of molecular spins on graphene. Nature Mater 15, 164–168 (2016). https://doi.org/10.1038/nmat4490
Scientific Reports (2019)
Nature Physics (2019)
Magnetic graphene/Ni-nano-crystal hybrid for small field magnetoresistive effect synthesized via electrochemical exfoliation/deposition technique
Journal of Materials Science: Materials in Electronics (2018)
Nature Communications (2016)