Modelling in Molecular Spintronics
Ecole Normale Paris-Saclay
Molecular spintronics is an emergent field combining the flexibility of molecular electronics and molecular magnetism with the advantages of spintronics. Its main goal is the manipulation of the electron spin by a wise combination of ad-hoc molecules and inorganic substrate. Besides the rich magnetic behavior resulting from the interaction between a magnetic molecule and a metal surface, or vice versa, additional functions such as switchability by external parameters (light, voltage) can be integrated. This multi-disciplinary field offers a wide range of routes towards spin-based devices with potential technological applications in information storage and processing– However, due to the very large number of possible material combinations there is an urgent need for fundamental understanding, guiding concepts and tools to scale up and systematize the search of new smart functional molecular designs.
Molecular spintronics has emerged for several (sometimes contradictory) reasons. Probably the most important feature is that molecules are much more versatile than solid-state solutions as they offer an almost infinite range of possibilities and their electronic, magnetic, transport properties can be finely tuned. This profusion of molecule/substrate combination opens up new possibilities in terms of spintronic applications, most of them being still unforeseen at the moment. However, in order to avoid getting lost in a jungle of multiple options, a truly interdisciplinary approach and fundamental driving concepts are crucial to clear up the way that will allow to come out with new practical solutions.
In the recent years the concept of spinterface has emerged in molecular spintronics, showing that the magneto-transport properties of molecular based nano devices are essentially governed by the interface between the molecule and the substrate. In particular the “matching” (or “unmatching”) of orbitals between the two materials plays a crucial role. Therefore the manipulation of spin at the atomic-scale can only be achieved by a deep understanding of the quantum mechanics of the system at the level of the atomic orbitals which are the elementary “quantum units”. However, despite the broad agreement concerning the spinterface concept, it has not really been used to devise strategies for the design of new materials or devices.
Density Functional Theory provides a very powerful framework together with unique modelling tools to describe at the quantum-mechanical level the physical and chemical properties of the hybrid systems involved in molecular spintronics. It can, not only describe the equilibrium electronic and magnetic properties, but it is also possible to determine the electronic transport through such systems via Non Equilibrium Green Function (NEGF) formalism.
The goal of this modelling school is to provide the main basic concepts in molecular spintronics and introduce some DFT-based codes to model electronic, magnetic and transport properties of molecules in interaction with a substrate.
The school will consist in a series of courses (in the morning) followed by hands-on sessions (in the afternoon).
Quantum Chemistry (C. Calzado)
DFT+U (A. Floris)
Hybrid functional (T. Markussen)
Molecules on surfaces (C. Barreteau)
Spin current and magnetoresistance through molecules (A. Smogunov)
Magnetic interactions (B. Sanyal)
Non Equilibrium Green Function (M. Brandbyge)
Electron-phonon interaction (T. Gunst)
Spin excitation (N. Lorente)
Hands-on sessions will illustrate the concepts presented during the morning courses.
Mads Brandbyge (Technical University of Denmark, Lyngby) - Organiser
Troels Markussen (Synopsys) - Organiser
Cyrille Barreteau (CEA Saclay) - Organiser
Alexander Smogunov (CEA Saclay) - Organiser