The action has been organized into six work packages: WP1, WP2 and WP3 were related to the scientific work, WP4 to the PI training activity, WP5 to the dissemination and WP6 to the administrative part.
WP1 (months: 1 to 21): this WP was devoted to the realization of micro and nanostructures of selected Weyl semimetals. Two strategies have been followed:
• a bottom-up approach, consisting in the growth of thin films of selected Weyl semimetals by pulsed laser ablation (PLD);
• a top-down approach, consisting in the mechanical exfoliation of thin flakes from bulk single crystals.
WP2 (months: 2 to 22): in this WP we fabricated micro- and nano-structured devices to perform electric and thermoelectric transport property measurements on thin film and flakes obtained in WP1. To this aim we used optical and thermal scan lithography methods and focuse ion beam (FIB) techniques.
WP3 (months: 3 to 24): this WP was dedicated to the characterization of the micro and nanostructures realized in WP1 and WP2 through electric and thermoelectric transport properties as a function of different parameters including temperature, magnetic field, uniaxial strain, sample geometry.
WP4 (months 1 to 24): this WP included all the training activities performed by the PI, including: PLD techniques, x-ray diffraction, SEM and AFM microscopy, optical and thermal scan lithography and FIB methods.
WP5 (months 1 to 24): this WP was devoted to the dissemination activity. Some of the scientific results have been so far included in 2 publications as articles. The PI gave 3 seminars in international scientific institutes, participated to 2 conferences/workshops and he was member of the organization committee of 2 workshops. In addition, the PI participated to 2 outreach activities.
WP6:(months 1 to 24): this WP was dedicated to the management of the project.
Overview of the scientific results
-Thin films of Mn3Ge. TOP-WSF realized thin films of Mn3Ge, one of the most promising material in the field of antiferromagnetic spintronics. Although the optimization of Mn3Ge thin films will require more research time and energies, the action contributed to the identification of a protocol for their fabrication.
-Nanostructures of PtBi2: one of the most relevant result of the action regards the realization and characterization of the transport properties of flakes of PtBi2, one of the most intriguing materials among recently discovered topological non-trivial systems, hosting both Weyl semimetallic state and 2D superconductivity.
-Uniaxial strain on micrometric samples of W1-xMoxTe2: TOP-WSF demonstrated that the electronic properties of micrometric single crystals of type-II Weyl semimetals W1-xMoxTe2 are very susceptible to mechanical deformations of their crystal structure, showing the potential of this compounds in the field of straintronics.
-Weyl semimetal phase in MnBi4Te7 compounds: TOP-WSF experimentally identified Weyl semimetal state in the magnetic topological insulator MnBi4Te7 under the application of an external magnetic field. This is an important outcome, because it evidences that MnBi4Te7 hosts different non-trivial topological states, namely topological insulator and Weyl semimetal, in a single system.
-On-chip thermoelectric devices. As an important technical result, TOP-WSF realized different designs of on-chip devices for thermoelectric measurement, exploitable to different types of samples even outside the project.
