Single-molecule devices with graphene electrodes

Abstract

Several technological issues have to be faced to realize devices working at the single molecule level. One of the main challenges consists of defining methods to fabricate electrodes to make contact with single molecules. Here, we report the realization of novel spintronic devices made of a TbPc single molecule embedded between two nanometer-separated graphene electrodes, obtained by feedback-controlled electroburning. We demonstrate that this approach allows the realisation of devices working at low temperature. With these, we were able to characterize the magnetic exchange coupling between the electronic spin of the Tb magnetic core and the current passing through the molecular system in the Coulomb blockade regime, thus showing that the use of graphene is a promising way forward in addressing single molecules.

Molecular single-ion magnets based on lanthanides and actinides: Design considerations and new advances in the context of quantum technologies

“…A promising and fundamentally different approach was proposed in 2003 by Ishikawa and co-workers [14], who successfully demonstrated that slow magnetic relaxation could occur in mononuclear lanthanide complexes, such as those in which a lanthanide (Ln) ion is sandwiched between two phthalocyanine (Pc) ligands, (Bu4N)[LnPc2] (Ln = Tb III (1), or Dy III (2), Bu4N = tetrabutylammonium). This rather unexpected result marked the beginning of a new era in single-molecule magnetism, with many research groups investing a great deal of effort in trying to understand this behaviour [41][42][43][44][45][46][47]. Real progress has been made in determining which factors affect most significantly the spin dynamics of Ln-SIMs [17,48].…”

Perylene-Diimide Molecules with Cyano Functionalization for Electron-Transporting Transistors

“…From the previous discussion, it is clear that contact effects at the organic semiconductor/electrode junctions play a key role and a considerable effort is needed to properly engineer the properties of electrical contacts in short-channel architectures. Graphene and graphene-based materials have been recently considered as interesting electrode materials for field-effect devices based on organic semiconductors [98,99], graphene nano-ribbons [100], and single molecule junctions [101]. When used as electrode, graphene takes advantages of its intrinsic semi-metallic nature, in addition to its excellent mechanical and optical properties, and closing the technological gap in terms of sheet resistance and optical transparency [102] with the more common transparent electrodes, such as indium tin oxide and other carbon-based alternatives.…”

Stable-radicals increase the conductance and Seebeck coefficient of graphene nanoconstrictions

“…1,2 It was recently demonstrated that stable electrode gaps below 5 nm can be formed using electroburning of graphene junctions. [3][4][5][6] Motivated by recent experimental progress in using such electrodes to probe transport through single molecules, 3,4,[7][8][9][10][11][12][13][14] theoretical studies have also focused on the electrical properties of graphene nanoconstrictions formed by incomplete electroburning of narrow graphene junctions. 3,[14][15][16][17][18] Graphene nanoribbons with zigzag edges have been predicted to show half metallic and spin filtering properties, 19,20 with high densities of states near the graphene Fermi energy, which are attractive for thermoelectricity.…”