title: Controlling electronic access to the spin excitations of a single molecule in a tunnel junction.
abstract: Spintronic phenomena underpin new device paradigms for data storage and sensing. Scaling these down to the single molecule level requires controlling the properties of current-carrying molecular orbitals to enable access to spin states through phenomena such as inelastic electron tunnelling. Here we show that the spintronic properties of a tunnel junction containing a single molecule can be controlled using the local environment as a pseudo-gate. For tunnelling through iron phthalocyanine (FePc) on an insulating copper nitride (Cu2N) monolayer above Cu(001), we find that spin transitions may be strongly excited depending on the binding site of the central Fe atom. Different interactions between the Fe and the underlying Cu or N atoms shift the Fe d orbitals with respect to the Fermi energy and control the relative strength of the spin excitations; this effect is captured in a simple co-tunnelling model. This work demonstrates the importance of the atomic-scale environment for the development of single molecule spintronic devices.
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk and Department of Physics & Astronomy, UCL, London WC1E 6BT, UK.
authors.forename: Ben
authors.initials: B
authors.lastname: Warner
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk.
authors.forename: Fadi
authors.initials: F
authors.lastname: El Hallak
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk.
authors.forename: Henning
authors.initials: H
authors.lastname: Prüser
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk and Department of Physics & Astronomy, UCL, London WC1E 6BT, UK.
authors.forename: Afolabi
authors.initials: A
authors.lastname: Ajibade
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk and Department of Chemistry, UCL, London WC1H 0AJ, UK.
authors.forename: Tobias G
authors.initials: TG
authors.lastname: Gill
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk and Department of Physics & Astronomy, UCL, London WC1E 6BT, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Fisher
authors.affiliation: Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool, L69 3BX, UK and Department of Applied Physics, Chalmers University of Technology, SE-412 96, Göteborg, Sweden.
authors.forename: Mats
authors.identifier: http://orcid.org/0000-0002-1443-9490
authors.initials: M
authors.lastname: Persson
authors.affiliation: London Centre for Nanotechnology, University College London (UCL), London WC1H 0AH, UK. c.hirjibehedin@ucl.ac.uk and Department of Physics & Astronomy, UCL, London WC1E 6BT, UK and Department of Chemistry, UCL, London WC1H 0AJ, UK.
authors.forename: Cyrus F
authors.identifier: http://orcid.org/0000-0003-1706-2147
authors.initials: CF
authors.lastname: Hirjibehedin