title: The classical and quantum dynamics of molecular spins on graphene.
abstract: Controlling the dynamics of spins on surfaces is pivotal to the design of spintronic and quantum computing devices. Proposed schemes involve the interaction of spins with graphene to enable surface-state spintronics and electrical spin manipulation. However, the influence of the graphene environment on the spin systems has yet to be unravelled. Here we explore the spin-graphene interaction by studying the classical and quantum dynamics of molecular magnets 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.
authors.affiliation: 1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Cervetti
authors.affiliation: Dipartimento di Fisica, Università di Firenze, Via G. Sansone 1, I-50019 Sesto Fiorentino, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Rettori
authors.affiliation: Istituto dei Sistemi Complessi, CNR, Unità di Firenze, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy.
authors.forename: Maria Gloria
authors.initials: MG
authors.lastname: Pini
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università di Modena e Reggio Emilia, INSTM RU, Via G. Campi 183, I-41125 Modena, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Cornia
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna 12, E-50009 Zaragoza, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Repollés
authors.affiliation: Instituto de Ciencia de Materiales de Aragón, CSIC-Universidad de Zaragoza, C/ Pedro Cerbuna 12, E-50009 Zaragoza, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Luis
authors.affiliation: 1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Dressel
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Rauschenbach
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.|Institut de Physique de la Matière Condensée, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Klaus
authors.initials: K
authors.lastname: Kern
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: Marko
authors.initials: M
authors.lastname: Burghard
authors.affiliation: 1. Physikalisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.|Department of Materials, University of Oxford, 16 Parks Road, Oxford OX1 3PH, UK.
authors.forename: Lapo
authors.initials: L
authors.lastname: Bogani