Towards TOPological insulator-based electronic devices for ROOm Temperature operation

Description du projet

Isolants topologiques pour l’électronique à température ambiante

Les isolants topologiques (IT) ouvrent une nouvelle voie à l’électronique quantique, mais leurs recherches ont été essentiellement limitées aux températures cryogéniques. Cela les empêche de réaliser pleinement leur potentiel. Dans cette optique, le projet TopRooT, financé par l’UE, démontrera les possibilités des IT en facilitant le développement d’appareils à température ambiante qui les intègrent. L’objectif du projet est d’établir une voie claire pour la création et la conception de tels dispositifs. L’équipe se concentrera sur l’intégration des IT dans les systèmes qui utilisent des aimants ferromagnétiques (AFM). Cette intégration permettrait de débloquer des applications essentielles dans le domaine de la spintronique et dans d’autres disciplines. Le projet vise également à mener des recherches approfondies sur l’optimisation des hétérostructures IT/AFM. Ces structures jouent un rôle essentiel dans la mise en œuvre des nouvelles technologies à venir, telles que SOT-MRAM.

Objectif

The proposal TopRooT (Towards TOPological insulator-based electronic devices for ROOm Temperature operation) aims at providing a route to novel electronic devices based on topological insulators. Nowadays, most of the research on topological insulators is for cryogenic (quantum)-electronics, but they also show huge potential for room temperature applications. To this end, a crucial technology is the integration of topological insulators (TIs) with topologically-trivial materials, such as ferromagnets (FM), enabling applications in spintronics and beyond. The proposal focuses on the study and optimization of TI/FM heterostructures and their application in spin-orbit torque magnetoresistive random access memories (SOT-MRAM). SOT-MRAM is at the forefront of the emerging technologies that enable a new generation of brain-inspired and energy-efficient computing, extremely relevant to drastically decrease the energy consumption of information and communication technologies, as stated in the European Commissions strategy on Shaping Europes digital future.
State-of-the-art implementation of SOT in TI/FM heterostructures is achieved at the microscale, which is not enough to achieve the needed high density of devices. Therefore, the proposal will specifically target the fabrication of nanoscale TI/FM heterostructures and pursue their implementation in full nanoscale magnetic tunnel junction (MTJ) devices for SOT-MRAM, addressing the integration and efficiency challenges that arise. This will be achieved by growing Bi2Se3 (the chosen TI system) by molecular beam epitaxy and by sputtering the FM and MgO layers for the MTJs. Nanoscale fabrication will be achieved by electron beam lithography and auxiliary techniques. The efficiency of the SOT in TI/FM heterostructures will be accurately quantified via Harmonic Hall Voltage measurements at room temperature, while full MTJ devices will be subjected to electrical transport measurements to obtain the relevant device metrics.