Exploring new spintronics device functionalities in graphene heterostructures

Graphene Flagship researchers have shown in a paper published in Science Advances how heterostructures built from graphene and topological insulators have strong, proximity induced spin-orbit coupling which can form the basis of novel information processing technologies.

Spin-orbit coupling is at the heart of spintronics. Graphene's spin-orbit coupling and high electron mobility make it appealing for long spin coherence length at room temperature. Graphene Flagship researchers from Chalmers University of Technology (Sweden), Catalan Institute of Nanoscience and Nanotechnology—ICN2 (Spain), Universitat Autònoma de Barcelona (Spain) and ICREA Institució Catalana de Recerca i Estudis Avançats (Spain) showed a strong tunability and suppression of the spin signal and spin lifetime in heterostructures formed by graphene and topological insulators. This can lead to new graphene spintronic applications, ranging from novel circuits to new non-volatile memories and information processing technologies.

"The advantage of using heterostructures built from two Dirac materialsisthat, graphene in proximity with topological insulators still supports spin transport, and concurrently acquires a strong spin-orbit coupling," said Associate Professor Saroj Prasad Dash from Chalmers University of Technology.

"We do not just want to transport spin we want to manipulate it," said Professor Stephan Roche from ICN2 and deputy leader of the Graphene Flagship's spintronics Work-Package, "the use of topological insulators is a new dimension for spintronics, they have a surface state similar to graphene and can combine to create new hybrid states and new spin features. By combining graphene in this way we can use the tuneable density of states to switch on/off—to conduct or not conduct spin. This opens an active spin device playground."