QUROPE Quantum Information Processing and Communication in Europe

Our endeavour is driven by one of the most ambitious technological goals of today’s scientists: the realization of an operational quantum computer, i.e. the development of devices governed by the principles of quantum mechanics. This goal is addressed by the new research field of molecular quantum spintronics, combining the disciplines of spintronics, molecular electronics, and quantum information processing. The building blocks are magnetic molecules, i.e. well-defined spin qubits, specifically functionalized to be integrated in nano-architecture devices. The goal is to establish reliable and reproducible methods for reading both electron and nuclear spin states of single molecules.

The visionary concept of encoding quantum bits within magnetic molecules is underpinned by worldwide research on molecular magnetism and supramolecular chemistry, within the European Institute of Molecular Magnetism (http://www.eimm.eu/). The main target of the project for the coming years is fundamental science, with a view on applications in quantum electronics.

            In this context, the main objective until now was to lay the foundation of the new research field of molecular quantum spintronics. In particular, the objective was to fabricate, characterize and study the first molecular devices (molecular spin-transistors, spin-valves and spin filters, molecular double-dot devices, carbon nanotube nano-SQUIDs, etc.) in order to read and manipulate the spin states of the molecule and to perform basic quantum operations. Among the most important results, we showed the possibility of magnetic molecules to act as building blocks for the design of quantum spintronic devices and demonstrated the first important results in this new research area. E.g., we have built a novel spin-valve device in which a non-magnetic molecular quantum dot, consisting of a single-wall carbon nanotube contacted with non-magnetic electrodes, is laterally coupled via supramolecular interactions to a TbPc2 molecular magnet [PhD of M. Urdampilleta (2012)].[i],[ii] The localized magnetic moment of the SMM led to a magnetic field-dependent modulation of the conductance in the nanotube with magnetoresistance ratios up to 300%. We also provided the first experimental evidence for a strong spin–phonon coupling between a single molecule spin and a carbon nanotube resonator [PhD of M. Ganzhorn (2013)].[iii] Using a molecular spin-transistor, we achieved the electronic read-out of the single nuclear spin of an individual metal atom embedded in a SMM [PhD of R. Vincent (2012)].[iv] We could show very long spin lifetimes (several tens of seconds). Finally, we proposed and demonstrated the possibility to perform quantum manipulation of a single nuclear spin by using an electric field only [PhD of S. Thiele (2014)].[v]