5/10/2023 0 Comments Field effect transistor![]() Ingla-Aynés and his colleagues were able to control the spin transport times in the material they used by applying an in-plane electric field and a backgate voltage to them. To measure spin transport, we used ferromagnetic electrodes that, combined with magnetic fields, allow us to measure in-plane and out-of-plane spins that travel across the graphene/WSe 2 channel." "Then, to promote proximity between the layers, we annealed our samples above 400 degrees Celsius. "We prepared bilayer graphene/WSe 2 van der Waals heterostructures using a dry polymer-based stacking technique," the researchers said. The second is WSe 2, which has a strong and anisotropic spin-orbit coupling. The first of these materials is graphene, which has a weak spin-orbit coupling and long spin relaxation length. Instead of using a single material, Ingla-Aynés and his colleagues used a combination of two materials with different significant properties. "More technically, by achieving a strong interaction between the layers, it is possible to imprint such an efficient spin-orbit coupling on the graphene (that acts as an effective magnetic field) that can reverse the spins without the need for applying a magnetic field and this is what we wanted to do." "We have particularly been exploring structures where a material with weak spin-orbit coupling (such as graphene) is stacked with a material with a strong spin-orbit coupling (such as WSe 2) and observing experimentally how this spin-orbit coupling is actually transferred into the graphene by proximity," the researchers explained. ![]() Van der Waals heterostructures, are a class of graphene-based 2D materials with layers that are not chemically bonded. Recently, Ingla-Aynés and his colleagues have been examining how heterostructures based on different 2D materials, also known as van der Waals heterostructures, perform in spintronics. Nonetheless, manipulating spins as they travel on graphene can be very challenging and has so far only been achieved using external magnetic fields, which is far from ideal for practical applications. Graphene is among the materials with the greatest spin relaxation lengths. "Our main goal is to understand how the spin of the electron can carry information and how this degree of freedom can help to create devices with new functionalities." ![]() Hueso and Felix Casanova, the researchers who carried out the study, told via email. "In our group, there is a long tradition of studying spin transport in multiple materials, such as simple metals, for instance," Josep Ingla-Aynes, Franz Herling, Jaroslav Fabian, Luis E. In their paper, published in Physical Review Letters, they used 2D materials to realize a spin field-effect transistor. Researchers at CIC nanoGUNE BRTA in Spain and University of Regensburg in Germany have recently demonstrated spin precession at room temperature in the absence of a magnetic field in bilayer graphene. Two-dimensional (2D materials), however, have unique characteristics that could provide new control knobs to manipulate spin procession. In experiments using conventional materials, engineers and physicists have so far only observed coherent spin precession in the ballistic regime and at very low temperatures.
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