Molecular Quantum Spintronics – MolQuSpin

A revolution in electronics is in view, with the contemporary evolution of three novel disciplines, spintronics, molecular electronics, and quantum computing. A fundamental link between these fields can be established using molecular magnetic materials and, in particular, single-molecule magnets [1], which combine the classic macroscale properties of a magnet with the quantum properties of a nanoscale entity. The resulting field, molecular quantum spintronics aims at manipulating spins and charges in electronic devices containing one or more molecules. Chemists have acquired a strong expertise in tuning, controling and manipulating the properties of the molecules (spin, anisotropy, redox potential, light, electrical field...) allowing the creation of tuneable devices with new functionalities.

In this context, the objective of the project is to lay the foundation of this revolution and hence to fabricate, characterize and study molecular devices (for example molecular spin-transistor and molecular spin-valve) in order to read and manipulate the spin states of one or several molecules and to perform basic quantum operations. MolQuSpin is designed to play a role of pathfinder in this –still largely unexplored - field. The main target for the coming years concerns fundamental science, but applications in quantum electronics are expected in the long run.

The visionary concept of MolQuSpin is underpinned by worldwide research on molecular magnetism and supramolecular chemistry, and in particular within the European Institute of Molecular Magnetism (http://www.eimm.eu/), and collaboration with outstanding scientists in the close environment of the partners. During the last years, the partners of the proposal have already demonstrated the first important results in this new research area. For example, we have built a novel spin-valve device [2] 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. The localized magnetic moment of the SMM led to a magnetic field-dependent modulation of the conductance in the nanotube with magnetoresistance ratios of up to 300% below 1 K. Using a molecular spin-transistor, we achieved the electronic read-out of the nuclear spin of an individual metal atom embedded in a single-molecule magnet (SMM) [3]. We could show very long spin lifetimes (several tens of seconds). We also provided the first experimental evidence for a strong spin–phonon coupling between a single molecule spin and a carbon nanotube resonator [4]. Our results open up prospects for new spintronic devices with quantum properties, which is the main target of this project. Task 1 concerns the synthesis, characterization, and deposition of molecules (design of double qubits molecular complexes, characterization of the physical properties of new spin clusters deposition of molecular nanomagnets and characterization). Task 2 concerns the fabrication and characterization of molecular devices (molecular spin-transistor, molecular spin-valve, hybrid molecular resonators, microwave on-chip coil development for spin and charge control and manipulation of SMM). Task 3 concerns the quantum manipulation of molecular spin states (basic quantum operations with one qubit and with coupled qubits).

[1] L. Bogani, W. Wernsdorfer, Nature Mat. 7, 179 (2008).
[2] M. Urdampilleta, S. Klyatskaya, M.-P. Cleuziou, M. Ruben, W. Wernsdorfer, Supramolecular Spin-Valve, Nature Mater. 10, 502-506 (2011).
[3] R. Vincent, S. Klyatskaya, M. Ruben, W. Wernsdorfer, F. Balestro, Electronic read-out of a single nuclear spin using a molecular spin-transistor, Nature 488, 357 (2012).
[4] M. Ganzhorn, S. Klyatskaya, M. Ruben, W. Wernsdorfer, Strong spin–phonon coupling between a single-molecule magnet and a carbon nanotube nanoelectromechanical system, Nature Nanotech (Feb. 2013).