Description du projet
Caractériser et exploiter les états topologiques dans les nanofils
Les états topologiques de la matière ont été découverts pour la première fois il y a une quinzaine d’années. Plus récemment, des chercheurs ont découvert que des états électroniques topologiques se retrouvent dans presque tous les matériaux connus pour chaque électron de la configuration cristalline. Alors que de nombreux matériaux topologiques 3D ont été identifiés, seuls quelques matériaux topologiques 2D ont fait l’objet d’une démonstration expérimentale. Le projet TOPO-NW, financé par le Conseil européen de la recherche, étudiera les états topologiques au sein des nanofils épitaxiés 1D, une configuration qui permet d’obtenir de nouveaux systèmes topologiques hautement accordables. Les chercheurs du projet accorderont sélectivement la structure de bande des états de surface, étudieront la réponse locale des électrons de Dirac de surface et s’appuieront sur les connaissances acquises pour créer des dispositifs électroniques et spintroniques à base de nanofils topologiques.
Objectif
Topological phases of matter have been at the center of intense scientific research. Over the past decade this has led to the discovery of dozens of topological materials with exotic boundary states. In three dimensional topological phases, scanning tunneling microscopy (STM) has been instrumental in unveiling the unusual properties of these surface states. This success, however, did not encompass lower dimensional topological systems. The main reason is surface contamination which is disruptive both for STM and for the fragile electronic states. We propose to study topological states of matter in pristine epitaxial nanowires by combining growth, fabrication and STM, all in a single modular ultra-high vacuum space. This platform will uniquely allow us to observe well anticipated topological phenomena in one dimension such as the Majorana end-modes in semiconducting nanowires. On a broader view, the nanowire configuration intertwines dimensionality and geometry with topology giving rise to novel topological systems with high tunability. A vivid instance is given by topological crystalline insulator nanowires in which the topological symmetry protection can be broken by a variety of perturbations. We will selectively tune the surface states band structure and study the local response of massless and massive surface Dirac electrons. Tunability provides a higher degree of control. We will utilize this to realize topological nanowire-based electronic and spintronic devices such as a Z2 pump and spin-based Mach-Zehnder interferometer for Dirac electrons. The low dimensionality of the nanowire alongside various singularities in the electronic spectra of different topological phases enhance interaction effects, serving as a cradle for novel correlated topological states. This new paradigm of topological nanowires will allow us to elucidate deep notions in topological matter as well as to explore new concepts and novel states, thus providing ample experimental prospects.
Champ scientifique
- natural sciencesmathematicspure mathematicstopology
- natural scienceschemical sciencesinorganic chemistrypost-transition metals
- natural sciencesphysical sciencesopticsmicroscopyscanning tunneling microscopy
- natural sciencesphysical scienceselectromagnetism and electronicssuperconductivity
- natural sciencesphysical sciencesopticsspectroscopy
Programme(s)
Thème(s)
Régime de financement
ERC-STG - Starting GrantInstitution d’accueil
7610001 Rehovot
Israël