Research

 

Work package 1. Spin Transport in Graphene

"The electron spin lifetime in carbon materials is expected to be very long both because of the very large natural abundance of the spinless nuclear isotope 12C  and the small size of spin orbit coupling.  This even led to propose  graphene as an optimal material to store quantum information in thespin of confined electrons. However,  most of the experiments show that the spin lifetimes are in the range of nanoseconds, much shorter than expected from these considerations. One of the research goals  of SPINOGRAPH is to  understand this issue, which lies at the heart of the design of devices were graphene is used as a passive component to carry spin currents. "
 
 
 

Work package 2. Magnetism in Graphene 

The electon transport and optical  properties of graphene   are unique in many counts,  because the two quantities that control these properties in other materials, the gap energy and the density of states at the Fermi level,  vanish. The spin properties of graphene are also different.The formation of magnetic moments in magnetic materials is most often associated to the reduction of Coulomb repulsion for electrons occupying degenerate atomic levels  in open  d and f shells. This phenomenon is understood since the early days of quantum mechanics and accounts for our understanding of magnetic materials based on transition metals and rare earth.
In contrast, graphene  is expected to host  of a different kind of magnetic moment that occupies at least 3 atoms and is associated to degeneracies  at the molecular level.  These magnetic moments emerge at the zigzag edges of graphene as well as at vacancies and in the neighbourhood of chemisorbed atoms, such as hydrogen and fluorine.  One of the goals of SPINOGRAPH research is to understand the emergence of local moments in functionalized graphene and their impact on transport properties.
 
 

 

Work package 3. Control and Manipulation of Electronic Spin in Graphene Devices

The manipulation of electronic spins has been demonstrated in other material systems, such as metals and semiconductors, by means of a large variety of techniques. In SPINOGRAPH we intend to implement some of these ideas in graphene devices as well as to try new approaches taking advantage of graphene's unique features, most notably, its  two dimensional character. Specifically, we intend to explore the following ideas:
 
Engineering ferromagnetism and/or spin-orbit coupling in pristine graphene by proximity to ferromagnets
Spin transport in graphene nanoribbons
Manipulating spin states in graphene quantum dot devices